I don't think you understand about blue born, many people are confused by the term blue since Yorkies are known for their “blue” coat. A blue born is something different, their hair has a greyish color and sometimes, their hair never really grows. Some are hairless and have skin problems, and some die before the age of three. They should never be bred, but people keep breeding them, and unsuspecting buyers don’t understand the health risks involved. Yorkie puppies all have blue eyes, especially when photographed. Your dog probably is a chocolate and there are no known health problems for the chocolate as there are for the blue born.
Goldenray Genetics Chocolate Yorkies Red Golden or Yorkie Blue Borns CDA. I personally don't believe people should breed for them, just because there are too many pets available, and the only breeding being done should be to preserve the breed.
Your little girl while adorable, doesn't look purebred to me because the hair on the leg resembles fur not hair as seen in yorkies. Sometimes people mix another breed into the dog, in order to get unique colors.