I have a crush on a girl I don't know. Advice?

We don't know each other that well. We just have a lot of the same friends. Anyway, I always thought she was amazingly attractive, but I never liked her that much. She told one of my friends she had a boyfriend, then later, we found out that she didn't. Plus, I'm kind of interested in meeting someone new anyway, I'm not really attracted to any of the girls I know already. Being that it is summer time, I don't see her that much. I ran into her once, when she was hanging with one of my female friends. The thing that's bugging me is that I keep thinking about her, when I hardly know her. And I'm not sure if I like her because I'm interested in getting to know her, or just trying to rush things because more and more of my friends are getting into relationships. What do you guys think? And any advice on how to handle it?