Hi Julie, welcome
Just so you understand some of the comments posted above
you should read this
http://www.pets.ca/forum/showthread.php?t=12240
and what is meant by a reputable breeder
http://www.pets.ca/forum/showthread.php?t=18613
I would recommend a puppy wellness visit with the vet within the first week and to have vaccinations done if needed, take a stool sample with you so it can be checked for internal parasites, as a deworming or another deworming may be necessary, normally a reputable breeder would have a pup started on a very high quality food and would make it a requirement that you also feed or the health part of the contract is voided, in the case of chineses crested puppy the breeder recommended Canidae. In the case of your pup it likely has not been fed a high quality food since it was bred for profit rather than to improve or keep the standard of the breed as in the case of reputable show breeders.
I would suggest possibly taking out pet insurance since you won't know if their are genetic health problems could save you a lot of money, and some genetic problems can be very expensive to treat eg with legges calve perthes could cost around $5,000, with VWD that is a blood clotting disorder to be on the safe side when it comes to spaying and neutering have blood testing done prior to surgery, a transfusion may be needed to get the pup safely thru surgery. because of possible renal issues in shih tzu's it is important to feed a high quality meat protein based diet
A list of shih tzu health issues
http://stfsc.bizland.com/health.htm
poodles
Cushings
Gastric Dilatation - Volvalus ( Bloat )
Epilepsy
Hypothyroidism
Optic Nerve Hypoplasia
P R A
Legg - Calve - Perthes
Sepaceous Adenitis ( SA )
Addison's
Patellar luxation
Von Willebrand's disease ( vWD )
Hip Dysplasia
This is not to say that your pup can't make a wonderful pet, I have had wonderful mutts, just that there are higher health and temperment risks involved. And I am not wording this to crush your happiness just to forewarn you of what you could expect, giving you either the opportunitity to change your mind or at least protect yourself from possibly vet high vet costs by obtaining pet insurance, I have made a couple of mistakes myself and the lessons were hard painful ones, as a result I try to warn others so they do not have to go through the same pain.
Looking forward to pictures of your new baby whether she is this one or another.