You guys are going about this all wrong...it doesn't matter worth a damn if shes interested now, you gotta go in and work your stuff! People on this site overanalyze way too much nowadays with "Does she like me" "She once twirled her hair while i was following her to her next class! I don't think she saw me, but my AURA must have been turning her on!" WHO CARES IF SHE LIKES YOU. If she does, great, you approach and get some, if she doesn't, you had more balls than most of the othre guys in this world, and it gives you experience.
Moving on. Im sure there's some passing time or something between classes. Go to class maybe 2 or 3 minutes before it starts and when she comes in walk up and say...ready for this?
"Hey!"
Works like magic....