Just my opinion anywho, breeding should be left to the professionals who are there to improve the breed
But looks like I'm the minority here on that topic, so you do as what you believe is best for you and your dog.
Nancy, really I never heard of that before. My sister's shih tzu was I'll say 8months when he bred with my dog, Princess and none of the pups had any sort of deformations, unless you count really cute bi-color eyes in one pup
But of course like with anything, it doesn't happen in all cases. Two pups didn't make it, because they became chilled few days after birth. But thats good to know, never knew that. Thanks for that bit of new information.