ask her out. if she says no, stop talking to her. nothing is more frustrating than trying to persue after she refuses. she knows your interested by then, and it becomes a drag along game. if you stop talking to her, she wont think that you are chasing her, and that drives girls. they wanna know how you feel about them, until you tell them, and then its old news. plus you dont want to get stuck in "the friend zone" because youll never break away from that.
so ask her out, never overpersue. when you get her out, stay cool, and be interested in what she has to say, but not desperate. if you act like its no big deal that you are on a date, she will feel more comfortable because you seem comfortable. if you are too desperate, she will get weirded out.
ive learned that people already have an idea of their perfect mate in their head, and that when you go on a first date, that person wants you to be the "ideal" one. if you talk too much, especially about yourself, you give away that mystery, and they become disinterested pretty quickly. ive missed out on quite a few awesome (and hot) girls because i was over anxious and talked too much or tried too hard to impress them.