Maybe it's an idea to take a picture of her teeth?
Tillo also had an overbite when he was younger, but he 'grew into it' Maybe you can contact your girl's breeder and ask him/her what he/she thinks. Have you told the breeder you were looking for a bitch to breed and can you give her back to him if she's not what you 'expected'?
Of course there are more (health and character etc) thinks to 'worry' about before breeding your girl. What if you decide to keep her and then in a year there is an other reason why you can't breed her.. are you going to give her away then? Is she only worth 'more work' if she's breedable? And if your two dogs are fighting all the time, is that a good place for a young dog to grow up and for an adult bitch to give birth?
What if you give her away, bring a new bitch to your family and she's not good enough to breed? Does she have to go also? And your other dog, does it like a companion? Or does it fight with all dogs/bitches?
Lots of questions