Tessy sounds like she's going to be a fun dog with those two breeds in her background. Both breeds love to play and interact with their people, and the pits, especially tend to bond very firmly with their people.
Keep plenty of toys for her to play with, and start playing games with her as soon as she shows any interest. You'll have to be firm with her, and spend time training her as Serena says, but she should respond well to praise and affection from you. One thing about both the labs and the pits, they are breeds that expect to follow commands from their people, so that should give you a head start. You can enjoy teaching Tessy and have a good laugh reading some of my laments about struggling with my Fila pup, Shiva. They are not only HUGE, but, unlike labs and pits and most other dogs, will make independent decisions and judgments about things. They also tend to be a bit mule-headed (with my apologies to mules), so we have to teach them to have good judgment.
It sounds like Tessy's got lots of great potential and can grow up to be a wonderful best friend. Have fun with her and keep us posted. Don't forget to post photos as she grows up, too. I'll bet she's going to be a beautiful dog.