If she gets pregant at 25, he'll be 52, and 70 when the kid graduates high school.
Discussion
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.