When I was really little, I wanted to be an archaeologist, an interest I still maintain. During my teen years, when I was heavily involved in high school drama and community theater, I wanted to be an actor, but decided the hardships of that path weren't worth it. I can get my performing fix in so many other ways than by doing it professionally (and I do)....though, I HAVE been in three TV commercials, but each time that happened, it was by pure chance, where a casting director saw me on the street and asked me to be in a commercial they were filming. I saw the commercials later on TV, too. :)
By the time I was a senior in high school, I had decided on novelist as the career for me. I won a creative writing scholarship to college, but the college was too close to home and I wanted to live on campus. So, I gave up the scholarship to go to a different school....and also to follow my high school boyfriend to the university he was attending.....and majored in Political Science to impress my great-aunt (who was paying for college), because she was a top official in our hometown city government.
I continued to write, mostly for the university newspaper, but also in creative writing elective classes and on my own. I started dozens of novels over the years, and abandoned them halfway through because I couldn't relate to my own characters.
I ended up spending a few years teaching, then doing background investigating, before becoming a freelance business writer.
It was only three years ago that I FINALLY sat down and wrote an entire novel from beginning to end. I've now written three full-length novels, and have two more in the works.
If I could go back and do it all again, I would have focused on making acting a real hobby that I put more effort into polishing, and made writing novels my career from the beginning, so by the time I was in college (where I would actually major in Creative Writing this time), I would be ready to write a full-length novel, and be a self-supporting novelist by the time I was 25, or younger. That's the ideal. In another universe, it's what I DID do. :)