My Age in Hair....

I am 42. Or i think I am. My birth certificate says I was born in 1971 so I must be. Is my real age 42? Is my age mental or physical? And how do I know. My dog is 3 so in human years he's 33, so does that principle work the same way for people? Because in my mind I am still 21 does that mean I am actually half my physical age? So when I'm 60 I will only be 30???? And more importantly does this matter???? I didn't think it did, but my 9 year old daughter just told me whilst playing the wii just dance game that "wake me up before you go go" was a really old song. No it isn't!!!  it is a song from when I was young and that wasn't that long ago was it??? What makes me old??? Is it the tired cynical outlook I seem to have adopted as life goes on, is it the fact I now get stressed and tired when previously I would have taken on the world and won? Or is it the fact that my ears and nose are now sprouting hair quicker than my head does? This I am convinced is the real true test of getting old, the more hair that grows out of my ears the older I am in real terms.So now when I look back on holidays from my youth, the drunken all nighters in the arms of some anonymous woman, the feeling that I could do anything and go anywhere, I won't feel sadness that I don't feel that way now and can't do those things I will feel sadness that those were the days my ears and nose were hairless.
Stay safe and be lucky.....