I originally registered as a Republican. My dad took me to a GOP office next door to one of his offices to register to vote. The form was already checked Republican. At the time, I would have selected that anyways...growing up in a conservative home, with conservative parents, in a conservative city. Seriously, when I was a kid, Republican Governor George Deukmejian used to fly the State helicopter down to one of my neighbors housing complexes to visit family. My family was more of a Sagebrush (SouthWestern) type Republican...wanting low taxes and wanted the government to keep out of peoples business. They barely exist any more.
I became disenchanted with the Republicans and wanted to change....I changed to Independent the year Ross Perot was running....and then I quickly realized that he was nuts. Nice charts...but he was nuts.
So I did a more research and the only party that I could find that supported LGBT rights, including marriage equality, as well as supporting protecting the environment was the Green Party. I have been a member of the Green Party ever since. I don't really follow their platform closely. I didn't entirely agree with the platform. They go too far to the left on some issues. But that does not really matter. The Green Party does better in local elections. They have not really had any influence on a National Level. Over time, the Democrats slowly moved closer to what a lot of the things that I liked about the Green Party. But I don't plan on changing parties any time soon unless California could make a difference in helping Sanders.