www.stellaryorkies.com
I have not bought from her, but from everything that I have seen thus far, she looks like a very reputable breeder. She has all her pups bile acid tested and full blood panels on them before she sells them to ensure that you have a healthy pup. You know what you are getting when you buy from her. She's such a nice lady too...She's a member of YorkieTalk...Her username is YorkieRini, I think. Take a look at her website.
And no, it's not too soon to start looking for the right breeder
It's good to have a relationship with your breeder before you actually get your dog. Good luck!!