As someone who is entering second semester of freshman college and has not had a steady relationship since grade 6, let me give you some advice:
Don't chase after women, just live your life, have fun with your friends. I made the same mistake for a very long time, I was always looking for a relationship, always disappointed when I didn't find one. Soon after I said "fuck it, I'll just start living" I was much happier person. So in short: let her know that you screwed up (in person) and tell her you'd rather start over. If she's not a bitch, she'll say okay and you'll resume being friends. If any part of her is interested in you, she'll probably give you a chance just for being honest and approaching her as a human being. If she says "fuck off", she's not worth associating with and you're better off walking away and forgetting about her.
Whatever happens, just keep living, and I don't mean survive, I mean LIVE.