No she is not more likely to turn on you guys because of her breed, that is myth that gets many dogs killed because people get rid of them because they are "going to turn on us". Growling at kids means she has not met enough of them and may be under socialized...how old is she? Make sure she meets LOTS of people but that it is always a good experience. Hand the people a treat to give her before they touch her so they know that they mean no harm. Did you say you got her from a breeder that would not let you see mom and pups? That is something you never want to do, it could mean she was a puppy mill with ill and neglected animals and your money went to support that. It also means that your puppy got very little socialization and could account for her timidness. You also did not know if the mom and dad had good temperaments or poor temperaments so who knows what your pups genetics are like, that is why it is important to always go to a breeder that lets you meet pups and mom and dad (or at least mom) and preferably who's dogs have their CGC (Canine Good Citizen) are therapy dog certified or some other proof of good overall temperament.
But just coming from a bad breeder does not mean she will be a bad dog. Dog bites mainly occur out of fear/lack of socialization which means something new (a different genre of people than she's used to...say kids) trys to interact with her and she gets scared and bites out of defense. So your duty to her is to make sure no group of people are new to her. That means people of all colors and ages, with beards, hats, umbrellas, on bikes, running, in wheelchairs, on crutches, short hair, long hair, tall people, short people, men and women etc. You also need ot make sure not too many situations are new to her. et her used to sounds like thunder, the lawnmower, the stereo and TV, children screaming as they play, dropping something by accident, tripping on a chair so it slides and bangs the floor, cars driving by, people jogging by, people riding their bikes by etc. If she does not get used to all these things and more she may develop a fear of them and fear can lead to bites. SO make sure she meets TONS of people and always watch her to make sure she is not afraid. If she is tell them not to touch her but to offer her a treat instead and then go away until she is more comfortable with people approaching. Bring her every where you can possibly go so that she can meet LOTS of people and LOTS of dogs (dogs once she gets her shots, until then only have her meet dogs you know are healthy and vaccinated).
Don't let people pet her on top of the head if she cowers or moves away when they do, it's a very intimidating gesture. Have them pet her body or chest instead, or even the side of her head as long as they don't reach over the top.
I have met both boxers and Pit Bull breeds and here is what I have to say, you have an EXTREMELY people loving and needing dog who needs LOTS of exercise. Both breeds are extremely active so should be getting multiple walks a day as well as some off leash running in an
enclosed area. They love people so don't listen to people who tell you she is going to be aggressive because of her breeds, many people on this forum have pitties so check it out. Check out this site:
http://www.dontbullymybreed.com/
And I agree with Redyre, find a puppy training class so your pup can learn something and get socialized. If you ever need help training anything ask us in the training or puppy section of the forum and we will help you out.
What you should be aware of with your breeds is that they tend to dislike other dogs so make sure you socialize a lot with dogs when she's young but keep and eye out for him not liking dogs as an adult, there is often nothing you can do about that but learn to get your dog to ignore other dogs and focus on you when they are around.
And once again please don't listen to ignorant people who tell you your dog is going to mean, they don't know what they are talking about, listen to people who have owned these dogs and really know what the breed is all about.
