This is hard to answer, because I've ALWAYS been a writer. I don't know any other kind of life. Writing is how I process, how I think, and I've been doing it as long as I can remember. In fact, it was a surprise to me when I grew up and realized not everyone does it.
I think for me, the best thing about being a published writer is getting to interact with the people for whom I wrote the stories. Knowing that my characters live in other people's minds and have helped them grow is an incredible thrill.