If she is giving you a play by play of why she can't hang out with you, she is actually avoiding turning you down, because girls don't feel comfortable rejecting a guy. So what they usually do is throw a bunch of excuses at you hoping you will eventually get the hint and go away. If a girl is interested she will go out of her way to see you, talk to you, text you, and if she can't she will suggest another time or make time. An interested girl don't waste time with excuses because that leaves room for another girl to step in so they act fast to accommodate.
In this case, I doubt she is interested.
If she was interested she would have made sure you have known it by being more attentive to talk to you and stuff in class.
General rule of thumb, some would disagree, but anyways, it takes a girl 7 seconds to determined if you are BF martial of not. Unless you have the gift of the gab, and are confident in chatting women up or really good looking....your chances are small.
Girls are more flexible with the looks and are more attracted to confidence. So you better work on that.