More disturbed about the amount of tiny baby puppies being resold through online listings, that can't have been in their new homes for more than a few weeks
Maybe she is just one that hasn't sold yet, I know a couple of people on here have picked up older puppies from breeders who had been choosy about where they went, I'd rather a breeder hung on until they found the right home.
Our recent ones came at six and eight months and our last bitch we picked up at nine months.
I never let mine go until they are 3 months, by coincidence I have Norfolks. It is hard and yes you do get attached but feel it's best for the puppy and I do try and check out the new owners very carefully, also would always take one back if things didn't work out for new owner.