What does it mean to feel a certain age?

Some people say “I am younger than my years” or “I feel so much older than I am” or “Age is only a number, it only matters how you feel inside”...well what does it all mean? What does it mean to feel like a certain age and how do we create this meaning, as people? Do we take cues from cultural messages about age groups and how people are allowed to feel in those age groups – think general policing of sexuality (where it’s only a certain age range that’s supposed to feel sexual and it’s considered appropriate…most people think this age range 21–45 feels safe)...

Do we connect this feeling like a certain age to physicality and why don’t we detach from society and just say something individual? I always say I am such and such age but I know I look younger and feel older…yet this makes no sense because I don’t think many older people feel or even think the way I do…

Thoughts?