In love...Don't know how to ask her out.?

I'm in love with a girl in my chem class. She's smart, funny, and absolutely beautiful. I am a master flirt except when it comes to girls I am seriously interested in. Both of our lab partners went away for trip because of band/chorus and we paired up. During our lab we both flirted with each other intensely...at least I think she was flirting. I noticed that as she stood close to me her feet were pointed towards me and she broke the "touch barrier" several times. I don't want to look to far into her actions towards me. When we are normally together, we fight like two elementary kids do when they like each other. Whenever I try to give her a hug she pushes away, but smirks as she does it... This is usually followed by a poor insult like "I need to shower now". I'm guessing that this is some form of playing "hard to get". I want to ask her out, but I need to be a little more confident that she likes me more than a friend back. Any and all feedback would be exquisite.