An attorney will be able to look into this for you. Most counties have deferred prosecution programs for possession of small amounts of cannabis, but that is offered in court at the discretion of the prosecutor. Call an attorney and provide more information about your situation and they will be able to help you sort it out.
This answer should not be considered legal advice, is for informational purposes only, and no attorney-client relationship should be assumed. Most lawyers offer free consultations and you should not hesitate to seek out a lawyer to assist you with this matter.
Who did the search? Police or school security? The statute of limitations for a misdemeanor in Illinois is 18 months, so that is how long the police have to file charges against you.
This is a difficult situation. The police and state's attorney have discretion on bringing cases. Do you have contact information for the investigating officer? Arranging a meeting with your parents and counsel present could get you the closure you are looking for by either finding out they have chosen not to proceed or that the process has begun and you can deal with the issues. Hopefully, they charge you as an adult and not a juvenile. If you are charged as an adult the effective penalties will be less as there will be less involvement with Court services. As I am often in Court have your parents call my assistant Dan London at 312-807-3990 to set up a private telephone consultation. At the Consultation we can discuss the confidential details we need to craft a strategic plan. These details sholud not be broadcast over the Internet.
This is a general answer and does not address the specifics of your individual case. To give the specific answer you need our firm needs you to come in for a consultation.