I just thought I would chime in with a bit of trivia that we show breeders use to approximate mature weight. At 8 weeks you triple the weight and at 12 weeks you double it to get a good guess on mature weight. So me thinks your are going to have a Big Girl!

But still cuter 'n a bugs ear!
One other bit of trivia....while your seller said they only had 2 mature yorkies on site.... for those of us who have multiple stud dogs, it is possible to have two different sires of one litter. Dogs continue to ovulate during their heat cycle. The AKC allows us to register a multiple sired litter but we have to DNA test EVERY puppy and the registration fee is really high!