Exclusive Luxury Matchmaking

I noticed her pretty early on but I'm shy and we didn't sit near each other in either class so I didn't really worry about it. I see her every weekday. Sometimes I make comments in group conversations. Recently, a group of us were standing around before class. She and I talked a little, some about our other mutual class. She seems like a really interesting person. I would like to talk to her more but she always rushes off after class and we don't sit near each other. I have considered casually sitting next to her in the MWF class but I'm shy and settled into my routine. How do I talk to her more? How do I find out if she's into chicks? She's tomboyish and sporty-looking but I know that no matter how many stereotypes she fits, there's no guarantee. If she is into ladies, what then? Do I ask her for coffee? I don't even know if she's old enough to ask out for a beer.