I'd say I should have started playing earlier too, I mean I started when I was 14 but only got serious until half a year ago (when I was 17).
I also wished I'd started singing earlier.
And I also regret not having participated with the theatre-day thing at school, if only I was able to find a singer that could I could have accompanied with guitar.
I saw a dude do a really bad job at Drifting, and a half-screwed up rendition of White Horse... It's like it's being rubbed in really hard.