i've always felt both younger and older than my real age (now 22). I too had a friend in high school who would pat me on the head condescendingly. At the end of high school I was hanging out with some friends and was really happy and acting kind of silly, and the guy i had a crush on said "my god, you're like 10 years old, are you ever serious?" What he didn't know is that i was acting like that because i was happy, partly because he was there. I was and am actually more serious in a lot of ways than many of my peers.
when i was little i thought growing up would be the worst thing ever and that all my fun would end when i got older, so i swore i would never grow up. now that i'm supposed to be grown up i wonder if i ever will be. my peers are living independently, getting married, moving across country, taking jobs. I still like to play on swings, havn't had a serious relationship, and sleep with a blanky.
on the other hand, i think creativity comes along with being child-like, and having a unique and refreshing perspective on the world. i think i often see things and make connections that other people don't. I think a child-like mind is very important for creative thought.