Probably somewhere between 16-20 so they're physically larger and have the capacity to actually give birth. There's a lot of focus on egg quality, which is good, you should be concerned about that, but there's a tradeoff. A woman who gives birth at, say, 10 or whatever, is far more likely to suffer complications during birth, and is more likely to give birth prematurely.
So, on the one hand, you need a woman strong enough to actually give birth (at least once successfully), but you also need a woman young enough to not have shit eggs.
