I am happy to talk you into spaying your girl!
Did you know that if you spay her now, before she ever comes into heat, you can all but eliminate her chance of ever getting mammary cancer? Mammary tumors are fairly common in older, unspayed female dogs and 50% are malignant.
Spaying greatly reduces the chances of a female dog developing this condition. In those females spayed prior to their first heat cycle, breast cancer is very, very rare. The risk of malignant mammary tumors in dogs spayed prior to their first heat is 0.05%. It is 8% for dog spayed after one heat, and 26% in dogs spayed after their second heat. http://www.peteducation.com/article....8&articleid=46
Don't let anyone try to talk you into breeding her. The complications that can arise from pregnancy in a toy breed dog are high. C-sections are very common. Breeding should be left to the experts.