>>941221237 (OP)
With age, the functions of the body start to decline. The reproductives functions of the female body is the first one to go. After 35 years, it's called a geriatric pregnancy because the body isn't made for that anymore.
If you want 3 kids, even if it work every time you try you will need 5 years to space them a bit. That mean you should start at 30 and not after.
It's wise to only make kids if you have spend a few years together.
TLDR: nobody want a Christmas present after the 25.