Why are my puppies paws small if she is supposed to grow up to be large?

I have an 8 week old German shepherd mix, well that's that I call her, but I guess shes really just a cute mutt : ), but anyways, her mom was half bull mastiff, half German shepherd and her dad was half collie, half German shepherd. They were both on the larger side of medium, im 5'3 and they came past my hips. But my puppies paws are just average/small size, and every one I talk to says she'll prolly just be small? I'm just wondering because I was really hoping for her to grow up big, and I heard that if a pups paws are big then they'll grow up to be big.