I know this is a bit cliche, but you're only as old as you feel. This reminds me of an incident I had at my younger brother's school (he is 17 years younger than me). They had a track and field competition and I had gone to give him support. I was getting something from the car in the school car park when I hear two kids talking. I do not remember what they were talking about, but I remember hearing one of them say "lets go ask that old guy". When I looked up at them, they were looking straight at me. I looked around the entire car park, and only after I failed to see another soul, I realized that I was the "old guy". I helped them out, but I will never forget the day a couple of ten year olds called a then 27 year old me an old guy.
Age is relative. I am sure there is someone somewhere in the world who would look at you and see a child. :-)
RE: When will I grow up?