Tell her you're going to experiment with drugs, alcohol and sex like never before and potentially never again. You will invariably face some situations that will test your comfort level, but you should not be afraid to say "no." Keep a mindful eye on your drink, always have a friend you can trust with you if you're going into an unknown situation (like a college party), and always keep condoms handy AND USE THEM. There is nothing wrong with experimentation, but don't let yourself get carried away; you don't want to end up addicted to anything, be it drugs/alcohol or partying or sex (or studying). Have fun, be responsible, and, most importantly, don't think that simply because you are in college, you are in a bubble. Plan for your future, seek out internships in a field you are interested in while you are still in school (I really wish someone had stressed this point with me). Your grades will neither make nor destroy your future, so don't stress out too much. Have fun.