Ok so in the aging tiers everything has negatives except for adult. The adult bracket has bonuses to their score. So the question is when you’re making a character do those bonuses get added to your character or are they purely there to age into?
If you look at the table, the left-hand column is the progressive modifiers. So you’d start off as youth and subtract 2 from stats, then progress to adult and add 2.
But for most uses you’ll just want the right-hand column cumulative modifiers, where there is no modifier for being adult.
I still don’t agree with either the fixed age bands, or starting “Middle Aged” so early for humans.
Maybe that’s because I’m rolling up on 44 and no loss of strength or mobility so far.