I got my puppy at 12 weeks exactly to the day, the breeder would NOT let me even take her one day early, we were getting a snow storm and she still said NO, not until she is 12 weeks old... she was really strick on this rule..
IM not sure if its a breeder thing with Yorkies or just a rule of thumb with just yorkies because I know with other breeds in America you can get them between 6 and 8 weeks..