breeding yorkshire terriers

Question
heya i have a 11 week old puppy and i wanna breed her but at which age can i do that  

Answer
Hi Claire

11 weeks old is too young to determine if your pup is even breeding quality.  You want to wait a year to see if she has any inherent issues that would compromise her health or that of the breed.

After her second or third season you could consider it.  Mental and physical maturity are more important than age.

Good luck