You really should keep them in separate rooms for 30 days as a quarantine period, because if your girl is carrying something and you don't realize it, Freddie could get sick and none of us want that! Do you have two cages? Three reasons: A, The quarantine. B, sticking them in together like that can be really dangerous. Even if they're doing alright together today, it's no guarantee that one of them won't suddenly turn aggressive and you could end up with dead chinchillas.
And finally, C. I'll leave talking about breeding to those members with experience (and you really, really should read through the breeding threads here to learn about breeding quality, the risks, the monetary and time sacrifices to having babies, etc) but if you do end up with baby chins, you're going to need another kit-safe cage (no ledges, small spacing between bars, etc) to put mom and the babies in for their safety and so that she can't get pregnant again because that would put a lot of strain on her.
Every good piece of info I've learned about chinchillas came from this forum, so I really, really recommend you read through the breeding threads and take into consideration what the experienced breeders who comment on this thread tell you, because I promise that all they want is for Freddie and your new lady to be safe, healthy, and happy.