Read your student handbook. Every school is different. Find out exactly what the written policy on alcohol in a dorm room is.
Some schools do not allow alochol, and can expel you for having it. Other schools don't allow it, but will not expel you. Other schools allow it if you're 21. Etc, etc.
The issues may be:
Are you of legal drinking age?
Can you have alcohol on campus?
Did you supply minors with alcohol?
Many states have fines for supplying alcohol to minors, so you may want to find out about that as well (as in, will campus police be contacting local city police?).
If there are to be charges, get them in writing. Then take your written charges to a lawyer. You do not want this to show up in your record or on your transcript (yes, some colleges will actually put it on your official transcript). Never go into any type of disciplinary hearing alone. Get advice from a lawyer, and have the lawyer go with you to the hearing if the lawyer recommends it.
And never take one of your buddies, who is pre-law, as your legal representation. I've seen students actually try to do this.
I'm an older guy, but my neighbor's kid was arrested by Michigan State University Public Safety (campus police) two weeks AFTER she took off her shirt--girls gone wild style--during a riot on campus after the basketball team lost in the final four (it was kind of an infamous campus party/riot/mayhem event about ten years ago). She was recognized on a tape someone filmed and arrested later. She was on a boy's shoulders yelling "woooo" while exposing her breasts. She was arrested, booked, charged, jailed, fined, and expelled. The boy was not charged in any way! She damaged no property, but was charged with contributing to the riot.
Anyway, she was profoundly embarrassed, and didn't want to tell her parents, and just pled guilty so she could get on with her life. Then it made all the papers, local TV news, her parents found out about her expulsion when she moved back home.
The moral here is--you are responsible for your actions, but the authorities also don't have a right to make an example of you or to ruin your life with a punishment that is much more harsh than the actual crime. Make sure you get the advice of a competent lawyer, whatever it costs.
I also heartily endorse an alcohol-free lifestyle. It is part of the path to happiness and success.
Good luck.