I really want to stay young for as long as possible. I'm still somewhat growing, so it's easier to stay in shape, I have a steady education and don't have to think about making money or making difficult choices, and I don't have THAT much responsibility yet.
...Life is easier the younger you are. 2011 was still probably the best year of my life so far, but that's because I'm happy and stuff :P
If you can be young and absolutely appreciate it, there is nothing better in this world.