How do you know her? Do you have any rapport with her? If that's the case, then you've already got your foot in the door.
By all means, ask her about how work is going, classes, anything you've talked about before. Get into a comfortable conversation with her. This will put you more at ease.
Try not to be flirtatious. You'll either fall flat on your face or you won't get the response you want. Joke around and have fun, but don't flirt. At least not very much.
Then when you've gotten comfortable, ask her "hey, would you like to have coffee with me?" Don't ask her to "hang out". Friends hang out. There's just something different about wording it "would you like to x-date idea?" Ask her to dinner, coffee, a movie, anything simple and fun.
Wear a nice polo and pair of jeans. No band or team t-shirts. Go to the event and talk with your friends or other familiar faces a little while. Then when you see her, work your way over to her, start chatting, get comfy, and then ask her out.
I used to feel the same way you do. Trust me, she most likely won't think that.