I had kind of the same situation coming into high school [except I'm a girl] and I was just starting to feel rather overwhelmed by peer pressure and such- which had never really happened before. So here's what I did to make sure I would make the best out of freshman year and not fall into the trap that seems to be devouring our generation: I got out a notebook and I wrote down promises to myself- things I wouldn't do, and things I would do, such as not drinking, smoking, or having sex, and showing people I love that I do, keeping my goals [like college] in mind at all times, and staying focused in school.
Obviously I'm not perfect and needless to say I've deviated here and there- but nothing extreme. I still keep my morals today and I'm going into Junior year. Just last week after my second drum corps competition [we won both] a lot of people were drinking in celebration. A couple of people openly asked if I was going to, as they did the competition before. I stuck to water, despite my absolute euphoria.
I really do believe that if you just sit down, decide what YOU want for YOU, and write it down, it will help you keep those promises to yourself. In the opening statement I wrote, "I do solemnly make the following promises to myself, which, besides those made to God Almighty, I hold most sacred above all else" I still believe that today- the promises you make to yourself are the most important you could ever make and are the most crucial to keep, because those decisions are the reflections of you as a person and how you live your life. And after all, what's more important than that?