Appeal from the Circuit Court of Lake County. No. 01-CF-3533. Honorable Mary S. Schostok Judge, Presiding.
 The opinion of the court was delivered by: Justice Gilleran Johnson
 Following a stipulated bench trial, the defendant, Brenda Kratovil, was found guilty of unlawful possession of Cannabis sativa plants (720 ILCS 550/8(c) (West 2002)), a Class 3 felony, and sentenced to 12 months' conditional discharge and 30 hours of community service. On appeal, the defendant argues that (1) the trial court erred in denying her pretrial motion to suppress evidence and quash arrest; (2) the trial court erred in denying a jury instruction regarding the defense of necessity as codified in section 7--13 of the Criminal Code of 1961 (the Criminal Code) (720 ILCS 5/7--13 (West 2002)); and (3) she is entitled to a defense of medical necessity. We affirm.
 On November 28, 2001, the defendant was charged by indictment with a Class 3 felony of unlawful possession of Cannabis sativa plants (720 ILCS 550/8(c) (West 2002)), in connection with an incident in which she was found in possession of 31 marijuana or cannabis plants and drug paraphernalia. The indictment alleged that the defendant knowingly and unlawfully possessed more than 20 but less than 50 Cannabis sativa plants.
 On January 17, 2002, the defendant filed a motion to suppress the evidence and quash the arrest that resulted from a search by the police of the defendant's home. On March 8, 2002, the trial court conducted a hearing on the motion to suppress. The defendant, whose vision is impaired, testified that on the afternoon of September 4, 2000, she heard a knock at her front door. She walked to the front door and opened the screen door. Officer John Willer of the Lake County sheriff's police identified himself and stepped inside. The defendant testified that she did not give Officer Willer verbal permission to enter her residence. However, on cross-examination, she admitted that she had voluntarily opened the front screen door and walked backwards away from the door. Once inside, Officer Willer informed the defendant about the marijuana that he observed growing in her back yard.
 The defendant testified that at this point, she presented her National Organization for the Reform of Marijuana Laws (NORML) card to Officer Willer. The NORML card informs cardholders of their constitutional rights. Specifically, the card states:
 "The U.S. Constitution prohibits the government from interfering with your right to remain silent, to consult with an attorney, and to be free from unreasonable searches and seizures by law enforcement. However, it is up to you to assert these rights. This NORML Foundation Freedom Card will help you do so effectively."
 The NORML card also instructs the cardholder to refuse to consent to any searches and to present the card to any law enforcement officers as a statement of the constitutional rights the cardholder wishes to invoke. The defendant knew about the content of the card. She testified that when she gave the card to Officer Willer, he dismissed it.
 The defendant testified that once inside, Officer Willer asked her for consent to search her residence. Officer Willer told her that if she did not consent to a search, he would leave two officers in her residence while he obtained a warrant. After obtaining a warrant, he would come back to her residence with a drug dog and "tear the house apart." The defendant then consented to a search. Upon completing the search of the defendant's residence, Officer Willer presented the defendant with a consent form and asked her to sign the form. The defendant testified that Officer Willer physically assisted her in locating the areas to sign. After she signed the form, the police left the defendant's residence without arresting her.
 Officer John Willer testified that he was a deputy with the Lake County sheriff's department and was currently assigned to the Metropolitan Enforcement Group (MEG). The MEG is a joint task force for gangs and narcotics. On the morning of September 4, 2000, the Lake County sheriff's department received an anonymous phone call that someone was growing cannabis in the backyard of the defendant's residence at 9905 Oak Forest in Beach Park. In response to the anonymous tip, at around 5:30 p.m. that day, Officer Willer and two other officers of the MEG, Officer Swanson and Officer Peters, drove to the area of the residence.
 The officers approached the defendant's neighbor, Scott Loesch, and requested permission to enter his residence, which Loesch granted. Officer Willer went into Loesch's backyard, which bordered the back of the defendant's residence. He looked over a wooden fence into the defendant's backyard and saw what he believed to be several Cannabis sativa plants growing throughout the defendant's backyard. Officer Willer explained that the MEG has provided him with experience and training on identifying Cannabis sativa plants.
 Officer Willer then went to the defendant's residence and knocked on the front screen door, which was closed. The inner door of the residence was already open when he knocked. The defendant approached the front door, and Officer Willer identified himself as a member of the MEG. Officer Willer informed the defendant about what he had observed from Loesch's backyard and asked if he could enter her residence to discuss the situation.
 The defendant gave Officer Willer permission to enter her house. He and the two other officers entered the defendant's residence. Once inside the defendant's residence, Officer Willer again told the defendant what he had observed. The defendant informed Officer Willer that she suffered from severe glaucoma and that cannabis helped to relieve the pain in her eyes. Officer Willer asked the defendant for her consent to search the residence for any other cannabis plants. The defendant initially hesitated and did not consent to the search of her residence. She asked Officer Willer what would happen if she did not consent. Officer Willer informed the defendant that he would leave an officer at the residence while he went to a judge who would possibly grant a search warrant for the residence. The defendant then consented to a search of the residence.
 Officer Willer and the defendant then went into the kitchen of the defendant's residence. There, Officer Willer presented the defendant with a consent form for her to sign to acknowledge that she had given the police her consent to search her residence. The consent form was boilerplate, so Officer Willer added an addendum to cover the shed in the defendant's backyard. He asked her to confirm the handwritten addendum and she initialed the added portion. The defendant placed the form close to her eyes but she initialed and signed the form without Officer Willer's assistance. After obtaining her signature, the officers proceeded to search her residence for additional Cannabis sativa plants.
 While Officers Swanson and Peters were searching the defendant's residence, Officer Willer and the defendant were in the kitchen. Officer Willer testified that he asked the defendant for identification so that he could fill out some paperwork. The defendant then handed Officer Willer her state identification card along with her NORML card. The defendant did not say anything with regard to the NORML card when she handed it to him. The defendant did not, at any time, verbally assert any of her rights that were written on the NORML card. Officer Willer believed that the NORML card was merely something that had inadvertently become stuck to the defendant's identification card while in her purse and that she had accidentally handed it to him. Because he was focused on the paperwork, Officer Willer did not read the NORML card until after the police had completed the search.
 A complete search of the defendant's residence revealed several Cannabis sativa plants on the second floor of the defendant's residence, in addition to the plants in her backyard. The officers also found drug paraphernalia in the defendant's residence. The officers seized the Cannabis sativa plants and the drug paraphernalia. Officer Willer informed the defendant that she would not be arrested at this time. The officers then left the defendant's home.
 Following the hearing, the trial court denied the defendant's motion to suppress evidence from the search and to quash her arrest. Specifically, the trial court found:
 "Ms. Kratovil voluntarily consented to the search of her residence. And the testimony from everyone is that the officer goes to the defendant's home and knocks on the screen door. The inside door is already open. The officer and Ms. Kratovil both say that the officer identified himself as a--as Deputy Willer and that he was with the Metropolitan Enforcement Group, and explained why he was there and what he saw. The deputy said that he asked if he could come in, and that the defendant said 'yes'; and she stepped back, and he came in.
 He again testified that he explained what he saw and asked if he could have a look around. That is, asked if he could search. Ms. Kratovil indicated that she was not sure, and at this point they took a couple of minutes. During this time frame she asked, 'What would happen if I don't consent?' And in response to her question the deputy explained that he would leave. He would leave someone there. Then he would go back and attempt to get a search warrant, and then come back. I don't find that coercive, but a response to a question asked by the defendant. There was no other conversation. Again, he indicated that there was silence, and then Ms. Kratovil indicated that they could search.
 Now, there is a question over this consent to search form. *** And the deputy indicated they walked into the kitchen, as well as Ms. Kratovil said they walked into the kitchen. *** They went into the kitchen and at that time he pulls out a consent to search form and explains to her what this is. And he says yes, he noticed that there was something unusual about Ms. Kratovil, that something was wrong with her eye. And, in fact, when she looked at the consent to search form she held it up very close to her face. She asked 'Where do I sign?' And the officer said, 'By the x.' *** At this time then the search is done both inside and outside the home.
 The deputy then talks about getting her identification card, and that--along with that is some other card that he did not look at until after. And I find it hard to believe that after Ms. Kratovil testified that having this card, knowing what was on the card, and knowing now what was going on inside her home that she would not have said to the officer, 'I know my rights. I know you don't have to be here. I know you don't have to search.' Nothing is said when this card is even taken out. And, so, in looking at all of the facts as presented by all of the witnesses, your motion is denied."
 On October 9, 2002, the defendant filed a motion in limine to present an affirmative defense of necessity as codified in section 7--13 of the Criminal Code (720 ILCS 5/7--13 (West 2002)). The motion also requested that she be allowed to assert an affirmative defense of medical necessity. On December 4, 2002, the trial court denied the defendant's motion. On January 16, 2003, ...