Hm. I don't know if I remember that far back in enough detail to specify my motivations at the time. But, hindsight and insight have taught me that I've always been a very creative person. I live frequently in my imagination, and spent nearly every moment of my childhood there (turns out, it was better than reality). I was always creating strange new worlds to explore, and characters with special abilities or traits that I craved to explore these worlds. Roelplaying was an easy fit for me, and has been a part of my life since. I can't really recall the very first time I started roleplaying with other people (aside from playground antics or the like). I do recall, however, being a part of a fan-fiction roleplaying group back on MSN Groups (when they still existed). Several, in fact. I even ended up running one before MSN Groups was shut down and everyone went their separate ways. I spent some time on Proboards and various small sites. But, most of the groups I've found are either too small, utterly dead, or so massive that getting involved in the community is impossible.
To be honest, I originally thought E would be like that, what with the thousands of members. But, since anyone can create any RP they desire, it makes it a lot easier to find people with whom to play. I think E is the best site I've come to in a long, long time. It has quickly become one of the few websites I actually spend time on (even if I disappear from time to time).
I don't know how many years I'll be here (though I do plan to be here for quite some time), or how many more years I'll be roleplaying. I've never really considered being 50+ and still roleplaying like this. I don't see any problem with it, it's just not an image I have in my head. Granted, I don't see myself being 50+, anyway. But, that's neither here nor there.