Good luck with your new puppy. Our Kyra weighed 1.2 (18oz) at 12 weeks and is still very tiny at 2.8 but Laddy who weighed 1.12 at 12 weeks is at 4.8 so my two have stayed pretty close to the charts. With these little ones you really can't know unless like YorkieMom1 said the breeder can trace their lines back many generations. I know you will love her no matter what because noone can resist those adorable yorkie faces.