I'd suggest that you call her on the phone to ask her out. And, you could just say something like, "You wanna go out sometime?" That way you're just going on one date, which she'll probably be more acceptable to since it's not answering "Will you go out with me?" That last question is a lot more pressuring. Anyway, if y'all go out and have a really good time, ask her out again, and eventually y'all are just understood to be "going out". That's how I did it, and I've been with my g/f for 1 1/2 now.