[Silmeria]

dont go like that find a way to make her a friend, now that she is a friend or you can have a normal conversation you can ask indirect questions thats your way to know if she has a BF or not, like for example in one of your conversation a thursday or friday go like "gahhhhh i have nothing to do this weekend and you? will you go out with your Bf?" now this is a crucial momment where will you know if she has a bf or not when you know about it you can act accordingly.
also if you have no ideas how to hook her in a conversation, you said she is in one of your classes is she smart on it? go and ask her about it, like what was homework or if she understood what the teacher said and make her explain you if she takes the time to means she is nice or she is interested in you as a friend at least.