Maybe maybe maybe at some point if you feel more comfortable, you could just talk to her and her gf and find out what they did to get where they are now, as far as being comfortable/knowing their orientation, etc...(some of us later in life, me included, would like to know, lol)

But seriously, might be good? Then you could talk to her too, and maybe you are attracted not only to her, but to the idea that she knows who/what she likes, and that confidence makes her that much more attractive to you.

Easier said than done though, after all, I am sitting here alone at the computer, and you are sitting next to her in class.....