Awww, well, much to my chagrin, Ginger gets shaved annually due to allergies (I shave her, so I'm sure it's not even as good a job as your groomer did)...she never seems to mind, and seriously, walks are a lot easier without "Miss Velcro-Butt" picking up everything she steps over.
To the previous poster, a yorkie's coat color often changes dramatically from the black and tan of puppyhood. Only time will tell. Look at the pics of grown up yorkies here just to see what I mean. Most began as black and tan pups. I find the easiest places to matt are under the arms and chin, so just be sure you're brushing those out daily, that should help.
To both of you, WELCOME TO YORKIETALK!!! I hope you grow to love it here!