at what age does someone become old?

when does middle age happen?

now that i am past the age of 40 should i have reached puberty, or be having a mid-life crisis?
is puberty just a small town in wales?
how do you know you've had a mid-life crisis and not just an everyday sort of crisis?

i'm confused.
is that my age?

answers in large print, or yelled through a megaphone, please.