Wow response is fast, this is nice.
Well to be honest I don't have a solid grasp on how long they should live but personally I think that 132-140 days(2.5-3 full seasons). I think that this is a nice balance considering that some humans you start off with are as old as 50-60 yrs old.
But the thing that really bummed me the most is the "age number". I was not expecting my solo human at his starting at his prime suddenly turned middle aged after an hour or so since I was shocked to know that one day is equal to a year.
Also I'm currently doing an Ancient playthrough( ferocious-ferocious) and reached autumn but there is still no merchant that came to visit, Is this normal for Ancients?.
Lastly, this game is pretty fun :)