In any event, shorter life spans means marry earlier.
Also, in the old days, work meant physical labor while today, it often means intellectual labor. That means today, marriage, sex should be delayed, compared with the old days. However, the biology has not changed as much as the culture and that produces conflict.
Actually, historians have found through reading records that in the middle ages people often married in their mid to late twenties, if they were poor or middle class. Only the very wealthy could afford to marry young, in their teens for instance.
A lot of what people think is historical fact is not.