I would just say don'the design your entire adult lives around being parents.
There is so much else to do.
I find the rush you're in a bit odd.
You say you're really ambitious, but you're going to choose pregnancy at 25?
A SAHD can't carry the baby, can't breastfeed the baby.
Is this a good time in your career to be working below your best for a couple of years?
To take 6 months out on full pay?
To potentially do it again in a few more years?
You can'take really reverse the roles. You will still be a mother with all that implies for your body and your baby's dependence on you.
I really don't think you've thought this through.
There are some very odd replies on this thread.
There is no real need to do this in August.