Hello. The others have answered the age issue. I just wanted to point out that breeding is something to be considered very carefully along with the reasons for breeding. It helps to know the genetic background of the hamsters or they can pass on genetic illnesses, or a mismatch in breeding can lead to some genetic abnormalities in babies that are born. I am not an expert in breeding myself but am aware it is a matter that needs a lot of consideration.
You would also need to be registered with a good exotic vet in case the Mother had difficulty giving birth or developed an infection or they can really suffer - sometimes a baby can get stuck as well. Plus Mothers can cull their babies if they are disturbed too soon.
With Russian dwarf hamster particularly I think, care needs to be taken when choosing breeding mates as most russian dwarf hamsters are already hybrids of campbells and winter whites so you'd be breeding hybrid with hybrid probably which I don't think is recommended. It is very hard to find pure winter white or pure campbells (even though pet shops may say they are) unless you get them from a breeder and they have a pedigree. Hybrid dwarf hamsters already have a genetic predisposition to diabetes and other conditions (neurological ones sometimes).
So I would strongly suggest that if you want to go into breeding hamsters, do a lot of reading and research first, ask experienced people (there are a number of breeders on here) and choose your hamsters for breeding carefully. And apologies if you already know all that
