Hi and welcome to Yorkie Talk.
Congratulations on your new baby Pixie. She was born on the same day as my girl's little singleton puppy! Yes, 8 weeks is a little earlier than what we recommend, but it's not unheard of. How much does Pixie weigh now? Sometimes breeders will let them go a little earlier if they aren't too small, though 10 weeks would be the absolute earliest I would even consider letting my pups go. Acutally, I'd love to keep them forever, but we know that's not possible.
The longer they are with mom (and siblings if any), the more they learn from them which will help them become better and more easily socialized as adults. That rough-housing and "play" that mom & siblings do together is actually valuable lessons being learned.
As a young puppy you might want to have puppy kibble available to her at all times (water also, but that goes without saying) and just watch that she IS eating. It doesn't take a lot to fill these little tummies, so you might want to weigh her every other day or so to be sure she is maintaining her weight or gaining some.
Good luck with your little girl and enjoy! I hope to see lots of her here as she grows up.