Baby teeth last longer. What's this bullshit about your first set of teeth lasts 5 to 10 years, then you're supposed to make it 60+ on the only other set you get? I'd make baby teeth last about 20 years.
People used to only live like 35 years most of the time. A tribe usually only had a couple of people who lived to old age, and became elders who were cared for by the younger people.