Not heard the phrase "cuddle bitch" before. Yes, that was rather a generalisation, but then us Brits aren't all reserved when it comes to sex and relationships!! Hmmm, can see you're in a difficult position here. Have you been consoling her and listening to her talk about her ex?
Well, for what it is worth. Here's what I think I'd do. Wait a few weeks, see what occurs naturally - you obviously get on great. Maybe at the end of term - Easter is just around the corner - invite her out for dinner. Nowhere too fancy, just somewhere nice and for a few drinks and then see what happens from there. That way, you're both on new territory, away from class and are out together as a friends/couple and away from everbody else.
I'll have a think...