She may have this type of coat, as explained by Joan B. Gordon. In her book, "The Complete Yorkshire Guide". I use this book as my coat Bible
Is her coat a little harsh, feeling like wire? She looks like she may.
It is explained this way in the book:
A puppy that has a wiry coat texture, with a tan that is a very bright red gold by four to five months, will as an adult do one of two things: First, if the puppy as it approaches five or six months, or at least by nine months, shows the transition from black to blue, the coat texture will soften to a silky texture. If the black coat does not show this transition to blue, the adult dog will retain the wiry coat which will never attain any great length.