She didn't notice you??
Yeah, I think I'd forget about asking for forgiveness, if for no other reason, it seems your main purpose for that is to get here to reconsider the restrictions, but it won't do any good, she has made it clear what she wants/doesn't want.
Someone mentioned she may be using you for help in class, is that so, do you help her much more than she does you? She may be using you but you are unable to see it, but maybe not...just be aware of that and look again.
Either way, I get it, you have a crush on her and you don't want to let go, even though there is nothing there to hold on to, it happens, but there is a point where you just have to respect her decision and hang on to a little self respect by not pushing it anymore.
I think I would back off, go with the thought she isn't interested and get used to it (sorry), don't be cold, but stop caring as much at least in regard to wanting a relationship. Not offering help is probably a good start, do that at the very least, and if you feel she is using you, maybe go a bit further. Whatever you do, don't be clingy, show definite lack of interest without being mean or obvious. Maybe start looking elsewhere too. If by slight chance she is going to come around, that is likely the only way she will, and if she doesn't, well that's where you are now anyway so nothing to lose.
I hate games but unfortunately that's the way it works sometimes. Also, I'm happy to be corrected on any of this, it's just all I can think of to do.