I consider myself pretty successful.  It all depends on how you measure success.
I wanted to fly airplanes, so I joined the Air Force, learned, and got good at it.  Then I wanted a civilian career, so I got into IT and got good at that.  I wanted to semi-retire at age 45, so I did, and continued in IT part-time to keep body and soul together.  I wanted to live in a hippie paradise, and I did.  I wanted to marry an intelligent woman with strong moral character, and I did.  I wanted to serve my community, so I became a volunteer firefighter.
When I realized that what I had really wanted all along was to transition, I did that too.  I wanted to be my real self, without having to hide, and now I am doing that every day.
When I was a little kid, I wanted to be three things: a pilot, a firefighter, and a girl.  I got to do all three in one lifetime.
I have never been rich, and I never will be, but that's not what success is about.  Success is about being the best you can be: setting goals and meeting them; being real.  Being real is the most difficult, but the most rewarding measure of success.