I actually don't remember how I got started in to roleplaying. As far as roleplaying online, I've been doing that since I was about... 10-12, on Neopets. The guild I was/am in is a roleplaying guild for Spirited Away. And part of what we'd do besides basic contests, was roleplay on the message board.
But certainly, like every kid, I also played make-believe games in real life, running around pretending and using our imaginations. I did that for years - though high school too, because of all the baby sitting I did. It was a way for me to use my imagination and be in a far off land like Harry Potter, Teen Titans, The X-Men, and various other universes from my childhood (Boxcar Children being the major one in my primary school days).