Hi there. Breeding Yorkies is a lot more than just putting a male and female together. It takes years and years of training and having a mentor to know how to do it correctly.
Bottom line is, if you are not experienced in breeding and whelping and if your Yorkie is not papered to meet AKC and YTCA guidelines, you really don't need to be breeding. You could end up with some recessive genes that cause the pups to have major health issues or just not be up to the breed standard.
Your title said "to spay or not to spay." Please spay. You don't need to breed this precious girl. Just love her as your pet. Spaying her helps protect her from ever accidentally getting pregnant..when a girl is in heat, male dogs of ALL breeds and sizes pick that scent up from way far away. You risk this tiny girl getting pregnant by a male that is not proper size and could kill her. I know you don't want her to die from being pregnant or trying to give birth to babies too large for her little body. Spaying her is not only the right thing to do...it's the most loving thing you CAN do.
