This might be more ideal for the offspring’s health because aging does increase risk of defects, but most mid-twenties are not in a financial position to just have kids
Men and women esp should be having kids by their mid twenties. The mutational load you pass on to your child when you're 40 is much larger than it is when you're in your 20s. Your kids will be all sorts of fucked up if you wait beyond your peak fertility.