As a Maths teacher I have to reply to the person that said we live to 80 so half it and that’s 40 so anything over 40…. grrr that’s really bad maths, that would be the second half of the middle part of your group…the first part of the middle part would come equally before 40!
I personally reckon you have to take childhood out of this as in my opinion its the middle part of your adult years not necessarily your life span.
Childhood runs to 20 in my opinion (properly mature and ready to stand on your own two feet at 20).
So life span of 80 years- 20 = a nice 60 years to split up to
0-20- Childhood/adolescence
20-40 Young adult years
40-60 Middle aged
60-80 Old aged/pensioner
80+ borrowed timer
Although it’s more a state of mind… maybe when you leave bikes and start playing golf instead?
