Can't remember a time when I didn't want to.
Very early on I loved adventure and set my heart on being an explorer-naturalist; the next Gerald Durrell. But with remarkable cynicism in one so young I convinced myself that far too much red tape existed to allow it and gave it up (a sadly mistaken belief, and one of my few real regrets; GD dealt with plenty of bureaucracy too, but never wrote about it, so I never knew.)
Meanwhile Farnborough '96 put flying LOUDLY in my mind (I bawled my eyes out through the entire Tornado display). At junior school there was an ancient computer with a ropey copy of Microsoft Flight Sim, which fascinated me. A chance shot with Combat Flight Sim in Toys 'R' Us got me hooked. Growing up I took flight sims more and more seriously until, aged 14 or 15, I remember very clearly thinking "I love this; this is fun. Why don't I do this for real...?" and firing up Google Search...
...and that, as they say, was that.