for me 25-30. i consider early 30's as late na.
assuming that i come to that point, by the time my first born reaches college im still far from retirement age. my body could still work overtime and double time to provide etc..
sa hirap ng buhay ngayon di na uso yung magiipon ipon for the future. feasibility of security is very slim at these thriving times. constant yung magtatrabaho or mabubusiness ka, dadagdagan pa nga minsan ng sideline. what is uncontrollable is time. kung medyo "seasoned" ka pa, mas mahirap ang predicaments.
plus palagay ko mas madaling makasabay yung ugali ng anak and mas maganda yung empathy ng father to child, if medyo magkalapit ang edad.
i maybe wrong, this is just my pov.