As said this sounds like a bad idea, breeding chinchillas is not something to take lightly, it's not like breeding most rodents, there are a lot of complications that can arise with chinchillas. Take a look at the horror stories link of the breeding and babies section on this forum and then see if you even still have the stomach for it. Also as said what it the goal of the mating? If it's just to get more chins it's not worth it, what is the plan for the babies? Especially if the chin's are of unknown pedigrees you could be unknowingly passing on genetic defects, even if neither chin show any signs they could be carriers of something. As said it can take months before they breed, and in some cases years, it's not like a cat or dog where you just put them together when the female is in heat and they breed, if they don't like each other they could kill each other. Physically a chin is never too old to have kits they don't go through menopause like humans, and chins can live 15-20+ years if properly taken care of and nothing goes wrong with them (malo, URI, accident, etc.). What you should be more worried about then age (assuming both are from good breeding lines) is if the female is physically capable. Just one example is not all chins are able to pass kits and c-sections cost thousands of dollars, there is round the clock after care and there is no guarantee mother or kits will survive it. My advice is if you or your friend want more chins is to look into going to a established reputable breeder or chinchilla rescue.
