Not based on anything you told us. Here are the valid reasons...
Google is your friend.
http://www.divorcenet.com/states/illinois/ilfaq_02
2) What are the grounds for annulment?
At the time of the marriage ceremony, one of the parties lacked capacity to consent to the marriage because of mental incapacity or infirmity (e.g., retardation, psychosis, dementia, or intoxication by alcohol or drugs) or was induced to enter into the marriage by force or duress or by fraud involving the essentials of marriage;
A party cannot consummate the marriage by sexual intercourse and the other party did not know of the incapacity;
A party was aged 16 or 17 years and did not have the consent of his parents or guardian or judicial approval;
The marriage is prohibited (see above).
3) Is there a time limit for getting an annulment?
Yes. The time limit depends upon the grounds for annulment.
Lack of capacity to consent to the marriage: either party may petition, but the petition must be filed no later than 90 days after the petitioner obtained knowledge of the grounds.
Inability to consummate the marriage: either party may petition, but the petition must be filed within one year after the petitioner obtained knowledge of the grounds.
Underage party: that party, or his or her parent or guardian, may petition for annulment prior to the time the underage party reaches the age at which marriage is permitted.

