You are as young as you feel. I find that our society puts too much importance on age. What does "act your age" mean anyway? Everyone is different, so everyone acts different for "their age".
I belive that people force themselves to act "older", and avoid or forget the things that brought them joy as children. Why is this? Are they afraid of what others may say or think? I guess this never happened to me since I do not care what others think about me, I gave up on that when I was in my early 20's.
You are only on this wacky ball of water & land for a limited time, live it up!