Talk with your mom. If you really love this girl, then your mom should accept her. Why did she get a bad 3rd party opinion on your gf? and from who?
The only solution is to make your mom understand that you are responsible enough to choose your relationships and that she shouldn't worry. She has to let you be yourself. If you don't want to confront your mom about it then you should probably let her go. But I still think that if you let her go, you should talk to your mom, cause she needs to change that over protective attitude, at least until she gets to know who's your company. Then she can worry about it if she doesn't like it.
