A long story this is.
I guess it begins around the 6th grade when I found a magazine/book which showed a bunch of pictures on how to do kung fu. I was fascinated with it. About the same time I wound up at my uncle's house for a week or so and they had a lot of books on Psychic stuff. These 2 events led to my reading everything I could on Philosophy, Ki, Chi, the martial arts and a huge desire to study the martial arts.
However, there were 2 things my parents were dead set against: one was little league and the other was martial arts. I recollect my father being royally pissed at my interest in studying it (reading about it was ok as that was cheaper than lessons). He aquiesed for a month but that was it. And it was.
I never really thought about punching, kicking or whatever for a number of years until a basketball game. In that game, I was unhappy which made someone else unhappy leading to an event that I lost on points. This led me to think "why the hell not", so I began thinking about the martial arts again. Coincidentally this happened right after I finished college so the parental yoke was completely lifted.
As was my wont, I went out and read everything I could. I didn't know much about Aikido but fortunately I stumbled across George Leonard's "The Ultimate Athlete". He said the right things and I was on my way. It also helped that the dojo was literally a 1/2 mile from where I worked and 2 miles from where I lived. I later got the first number down to 100 yards and the second to 1/2 mile.
As to why I stuck with it, I don't know. I actually mostly walked away from it for 3 1/2 years and don't really know why I came back. Both appear to have been good decisions though.