I'm 19, but I keep having these awkward moments where I put down 18 on forms, and than realize later on, oh crap I'm 19. or say I'm 18 when I'm actually 19 without thinking. It's happened a few occasions, than I realize and fix it up.
I do it quite often without realizing it, I don't feel any older, personally I don't feel any different from when I was 16.
I feel more mature, but not older. (I wouldn't call myself mature though, as I wear nappies)
I think we are all kids deep down.