What exactly do you mean by biting?--mouthing or play biting like puppies do, or do you feel she is biting you aggressively? What have you done to try to curb the biting? How do you behave when she bites at you?
To me (and I'm not sure I have a clear picture of the situation) she sounds like she's behaving like an overgrown puppy who lacks respect for you. If she gets out of control while playing, I'd stop the game and do some obedience work with her, or simply drop the toy, walk away, and become uninteresting.
Some NILF might be helpful for you. Google or search on the forum for NILF training (Nothing in life is free).
Does she get much exercise?
I agree that the best thing to do is to hire a trainer. If money is an issue, and your dog is not aggressive or disruptive around other dogs or people, you could consider a group obedience class with an experienced trainer (someone who trains working dog breeds would be better for you than a generic petco style class, most likely). These classes are usually much more affordable than a private trainer; in my area they are usually around $100 for a six week class. GSDs need structure, boundaries, exercise, training, and fair, consistient leadership-which a good trainer can help you to develop.
Last edited by sebrench; 09-23-2019 at 01:34 AM.