Wow! Lots of brass players on GH. Drummers, too, it seems.
I wish I had learnt an instrument in school (properly, as in taking it as a subject). I tried to learn mouth organ / harmonica (one of my dad's friends could play one well), but got nowhere. Tried keyboards, got nowhere.
I started learning guitar (on a 12-string

) in my final school year (grade 12 equivalent I guess) and picked it up really fast (surprising considering my previous efforts). In college I was in a little punk band with some friends and we all decided to try switching instruments.
I became interested in drums and started learning. Bought a kit and practised a fair amount, but didn't improve much

Switched to bass guitar. Similar story to drums, although a little better. Still can't jam on the instrument, though, which I consider to be a telling sign.
Back to guitar now. It just feels more familiar and comfortable than the others. I don't regret trying the others, though. Gave me a much better understanding of what's going on in a song.
I'd rate my skills as: Fool, Guitar, Bass, Drums.