Age gaps are good, and natural for society.
Men should be the older one in the relationship.
An older man brings more monetary value, and a younger woman brings fertility.
Discussion
And he'll be 65 when his first kid graduates high school.
Some people become parents as teenagers, some at 50.
Personally, I don't care what age someone becomes a parent as long as they provide the best life for their kids, and in all honesty we need more unplanned pregnancies because we're having a population crisis.
Though I think the ideal is probably a planned pregnancy around 25 perhaps.
If she gets pregant at 25, he'll be 52, and 70 when the kid graduates high school.
That isn't important.
My father kept on making kids until his 70s. They grew OK.
Not even in the middle ages the peasants had such mentality like yours. The older the man, the more he has to make an effort to compensate the gap so the deal tends to be quite good for both parties involved.