Hey... I hope I didn't sound too harsh but I've had a dog like you described (White Dog's mama) and she put me through it with her dog aggression, but I learned quickly where I could and could not take her and do with her. When you said that your dog bites you when she gets excited going after a squirrel do you mean she full on bites you or your hand gets nipped by accident? Gamer posted in the thread about putting her down and I must agree with that if your dog is turning on you in the commotion and excitement and biting you. That is unwarranted human aggression and an unsound pit bull. I have to redirect Kangol's attention quite often but he has never tried to bite or nip my hand. I have had to break up a fight between him and his dad a few times, but not one time did either of them turn and bite me for doing so. If your dog is biting you on purpose then I would have her put down; however, please consult your veterinarian and/or dog trainer... someone that knows your dog.
Hundreds of years ago when pits used to bait bulls and bears if any of them bit the hand of their master and hunter while doing so they were put down immediately.
Good luck and I hope everything works out for you and your girl!
Also, thank you for your comments on Kangol!