I am a junior at University at Stony Brook, Long Island, New York.
First of all, remember that once you're in college, everybody's going to treat you like an adult - in high school you got treated like a kid (if not you're lucky), and now no one's going to remind you to do the project on time.
You can do two things (if you live on campus, if you still live with parents, it's a little bit different) - you can either study or party. Partying means drinking, smoking weed, going to parties all the time, etc. First year, I partied, and second year, I studied, so I experienced both. I can pretty much tell you that the choice is yours - it depends on what do you want to do with your life. If you want to get a good job and be able to make good money - party on weekends, never miss classes (missing classes in college is very, very stupid, since you're paying for them), and don't do stupid things that could get you in trouble, unless you know you won't get caught. For example, you get caught doing hard drugs, for example (and you're gonna get tempted to do that, one time or the other), it could f*** all your life - you could never get a good job, etc, etc...But then again, college is the best time in one's life to party, so the choice is yours. Also - if you'll want to pledge, expect your grades to plunge that semester, because pledging takes a lot of your time. For some people it's worth it, for some (me included) not really. The only thing is, be smart about what you're doing and know your priorities, so you should be ok.
) but I've seen it too many times where a freshman just gets caught up in the excitment of being away from home and just "burn-out" or "Flunk-Out".