18-Year-Old Caught With Alcohol, First Offense

My question involves criminal law for the state of: Illinois.

Hello,
a few weeks ago I was out with my friends early in the morning in Forest Park, Illinois. I am 18 so I was not breaking curfew, but all of my friends were still 17. We were technically walking on private property, so a cop pulled us over. I had a beer in my hand, so I was cited for "possession of alcohol by prohibited person"(v.o. 3-3-11C). The first cop grabbed my backpack and proceeded to search it. All of the items in the backpack were legal for me to carry. My court date is in less than a month.

So my questions are:
-Since this is my first offense, what are the possible punishments?
-What will court be like for a small, criminal case such as this one?
-Should I hire an attorney?
-The cop told me that the citation he was giving me would not go on my record. However, he did not say whether that was true after I stood before a judge. If I am found guilty, will this stay on my record? Is there any way I can peaceably get through this and have it stay off my record(i.e. alcohol classes)?

Thanks, I really appreciate it.

Yes, you should definitely hire an attorney.

You're likely to have fines and probation, and may even be eligible for a diversion class which might keep this off your record - provided you complete the terms of your probation - but you're going to need the help of an attorney to obtain that.

If you were given a citation, it won't be a criminal conviction. Ordinance violations are fine only sentences. If you have a misdemenaor, it will be a criminal matter. What is the ILCS statute for this offense? Also are you going to Maybrook Court for this or to Forest Park?