I ran my first game in the Summer of 1978, a a little more than two months shy of a year after playing for the very first time.
A friend had the Basic Dungeons and Dragons game and since I was the only one among the potential players with any past RPG experience, I was voted GM by default. You can read a reference to this here.
I definitely prefer to run over playing as a PC and have since way back then. While I do enjoy playing more now, Gamemastering is still my first and foremost love.