How do i get this girl to forgive me?

You can't just prentend it never happend you really messed up. If you know where she lives is suggest you take a visit one day knock on her do look her square in the face and apologize. Tell her that it was a stupid mistake and you miss having her as a friend. Then if she still rejects you at least you can say you tried everything. Do this before meeting her in her college. Hope that helps