Average life span is pretty short for contemporary foragers (30-35 years). For that matter, it was short for agricultural peoples until fairly recently. Most people probably don’t know this. Most of the people who do know fundamentally misunderstand it. Today most people die when they’re old, moderately close to the average age of death. Back in the day, a very large fraction died when young, due to infectious disease and food shortages. And subincision. Most people who know about those short lifespans in the past somehow can’t really believe that infant mortality accounts for most of the difference. If the average lifespan was 30, they figure that hardly anyone made it to 40. I’ve had a doctor explain to me that that hardly anyone lived to be 70 in 1900 in the US (!).
We know that this is not the case in contemporary hunter-gatherers. If you make it to 15, you have a pretty good chance of making it to 60. Life expectancy at 15 was about 48 among the Australian Aborigines and 51 for the !Kung Bushmen. In some other groups, expected lifetime at 15 was lower, in the 30s. Still – even so lots of people made it to 60 or later.
A high average paternal age was only possible if quite a few guys lived well over 50 – but that happened.