6 weeks is ideal. You want to give them a good head start on life before sending them out into the world. But you may end up waiting a lot longer than that. I know even a few experienced and well known breeders who can't always get rid of all their babies.
If this is your first time breeding dragons, consider all the time, space, and money involved. To help prevent against tail and toe nips, you'll need to seperate the hatchlings to about 5 per rearing bin, so you may need quite a few of those. Then you'll need enough heat and UV for all of them, and thousands and thousands of crickets. Then if you get all that done, you may only sell half and then you're stuck raising the rest until you get them homes, and who knows how long it may take. It's very expesive and time consuming, and you might be lucky just to break even. It's certainly not a "cross that bridge when we get to it" kind of thing, because it could get you in far over your head.
If you put her in with him for a couple of weeks chances are fairly good she will get pregnant. If they get along ok, and you have the full intention of breeding them anyways, then go for it. If you don't really know and aren't prepared to drop a few hundred bucks and devote half of your spare time to raising baby lizards, you'd be better off keeping them apart.
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2.0 bearded dragons (Ocho / Domo-kun)
0.1 kingsnake (Rio)
1.0 ferret (Playstation)
1.0 cat (Wally)
0.1 dog (Tima)