How should I ask this girl out?

No it wouldn't be a bad thing, look on the bright side, your almost 21 too i'm sure. Girls like a guy who can take them out for a drink ;). Jk. No your doing a good thing, just invite her out after "Research", to just hang out. Grab a bite or something, be real subtle about thing :D. Don't force anything, talk, hang out, have fun! Good luck man! The only way to ask her to hang out is just asking her. There's not really an etchy way around asking her.