Kandy, I don't really advocate breeding chins, unless you have the best possible stock you can get, a terrific vet you can take them to in case of emergency, and a large savings account set up for vet bills. I personally don't breed chins (never have) because there are so many already looking for homes and I don't want to deal with the complications of birth, handfeeding, and death at this time.
Breeding any animal is a huge responsibility and even though there are rewards, there are also great losses. It is commendable you are doing your research beforehand, as there are many things to consider. Are you willing to lose your girls to delivery complications? Are you willing to handfeed every 2h around the clock if the kits are weak or motherless? Are you willing to keep all kits until they can be placed in good homes? It's a lot to consider.
Where did you get your girls from? Do they have a good pedigree at least three generations back with no history of malocclusion or other genetic problems? At this point they are much too young to breed. You need to wait until they are at least one year of age to even consider it. By that point, you might realize they do not have the best physical features (i.e. blocky, good weight, nice conformation, nice color, fur density etc.) worth passing on to future generations. This is not to say your chins aren't cute, they ALL are cute, but only a select few should be bred.
This is just the tip of the iceburg when it comes to breeding chins. I would recommend you read everything you can before deciding to buy that male. Go to chin shows so you can get an idea of what quality means in a chin. Talk to other breeders or ranchers. You have at least a year to do your research, so get informed as much as possible. Best of luck to you.