Man, I envy so much you canadians and americans. For you (well, maybe not all, but a nice percentage) learning to play an instrument (sometimes many!) growing up is a natural thing. A friend of mine got an american boyfriend and he could play drums at a pretty good level (Rush songs), plus he plays the guitar and once we went in a music shop and started to paly some Mozart sonata on the piano. I swear I wanted to punch him in the face. He is not a "pro" musician or something, mind you.
Here in Italy music culture is non-existant: I remember as a kid that sometimes I asked for a guitar or a keyboard and their answer was "First you learn how to play it, then we will get you one". WTF?! Now, I love my parents and they are by no mean bad ones, but if there is one thing that I regret in my life, is that I never learned to play when I was young, and they have a big responsability in that.
So I fell in love with music, then with the bass and felt the need to play it, and I bought one... at 27 (now I'm 30), with no musical training whatsoever. It's hard. Really hard, expecially considering that I like complex and technical stuff. All in all I don't think I play THAT bad and the switch to a (lined) fretless was easier than I expected, but I wonder what I would be able to do now had I started 20 years ago, and I rage.
And I have to use tabs and learn everything to memory which is a pain in the ass since I can't read sheets (try learning Hemispheres by Rush, 18 minutes and there are not two bars identical I believe...), and that has an effect on my constance (hint: is very low).
I had a brief foray into keyboards when I was 23-24 I think but without training I sounded like shit, so I stopped, and lost even more time.

Now I can do some simple things (my role model is Geddy Lee after all XD), but classical tunes and anything requiring two hands is really out of my reach, but that's ok.
TL:DR; If you know how to play an instument, keep practicing, and if you have kids, surround them with music and instruments!