For myself, I find I'm stuck at different ages, depending on the
  context. I suspect it's similarly true for most people, if not
  all.

  I'm thinking primarily of emotional responses.

  For example, I have an analytical curiosity that has an excited
  "I'm going to figure this out if it kills me" component to it
  that's very strong.

  I know for sure I've had that since I was 11 yrs old, so
  emotionally, when it comes to "figuring things out", I'm 11 yrs
  old... just with lots of new knowledge thrown in the mix.

  Humor wise? A very mature 9 years old. There's a fart? I laugh.
  Wait, that makes it about 6 years old, because I find puns and
  clever word play hysterical. "I see what you did there".

  But I instantly turn into a 43 year old Dad/Uncle/Grandpa role
  (I'm only Uncle but they all apply) when someone is trying to
  figure out a life-problem.

  [and occasionally, I turn into an 84 year old who is glad about
  this trip around planet Earth and go, "Yup, it was a life well
  lived"... strange because I'm not there yet, but if I practice
  that attitude enough, by the time I get there (if I do), I'll be
  'that guy' ]