How to keep a low profile in college?

I'm 21 and I'm going to a junior college (American River College) As I was looking around it looks as if most of the students are about 18 maybe even 17 and in their early 20s. They seem to act a lot like high school students and I want to steer clear and avoid them as much as I can and I want to keep a very low private profile in school and not get approached. How do I go about not having students get any first negative impressions of me or not any impression at all? I don't want any students to think anything of me and I want to be as private as possible. I have been picked on a lot when I was younger and I'm anxious that I'm going to be picked on in my new school. I want to turn over a new leaf and start fresh and try to not have students pick on me and/or call me names or get in fights. I'm trying to finish up as fast as possible and get my degree to go to a top university and come out making a starting salary of $150,000 a year by the time I'm 30. I don't have time to have some young 17-18 or early 20 year old immature idiots in my way. I want to study hard and finish up and do extracirricular activities while I'm in school. I want to come out with a 4.0 and higher! I'm mature, eager, and I can get things done fast and I'm determined!