If it's an appropriate weight for her current height, I wouldn't worry about it. She's still young with a lot more time to grow. Puppies can end up naturally smaller or bigger than their parents. I have a friend with a GSD puppy who is consistently 20-25lbs smaller than her littermates, but it's appropriate for her size, as she is just turning out to be a smaller dog. Whereas my puppy came from smaller parents but she is ending up larger!
Ryker: (USDAA) SR (DOCNA) C-BTA C-ISLA
Chandra: puppy in training!
Living forever in my heart, Solstice: (AKC) MX MXJ MJB (USDAA) PDCH (DOCNA) MEX-Bronze