I just came to a new school this year and I was pretty down for obvious reasons. And I came across this girl who is pretty and nice. However I feel I gave off a bad first impression because a guy stole my lunch money and I head butted him. Now I think I'm seen by her as too aggressive and an overall jerk. And I told a friend I met there I like her but then he told his friend and he told me she told some other people. I hit him in the stomach for that. I would like her to see the gentle, punk rock loving side of me. (And we both love punk rock). But she has a boyfriend so I feel if I try to be nice and friendly towards her whilst still being fairly hostile to others I think either she'll find out or her boyfriend will and he'll want to kick my ***. And I try to avoid violence if necessary. I really need help because I'd gladly cut off my pinky finger for her. I sound like a hopeless clown but still if someone could help me...

She is already involved so out of bounds.
Be her friend by all means, but DON'T try and make a move, as it will most likely go badly for you and you will lose any friendship.