You won't know anything until you look at the pup. If she doesn't fit your idea of what you want in your yorkies that are for breeding then pass on her, only you will know if she fits your criteria.
As for the ears, I think she is still young and they could go up when she gets older. When I got Scampers at 12 weeks old they were floppy. A week later I shaved them and taped them and to this day, at over a year old, his ears stay up. Scampers weighed 2.5 pounds at 12 weeks and now weighs 5.5 pounds. I would say 3 pounds at 12 weeks is a good weight but it is hard to know for sure.
Good luck with whatever you decide!!
