Did you always know you wanted to be a writer?
Yes and no.
I wrote a lot of short stories when I was young, and even sent a few in (to get rejected). In fact, below is a copy of my very first rejection note, from 1978. My mother saved this for years, and brought it out after I got published.
I was never serious about writing in college. I focused most of my creative energy on music, and was lead singer in a folk rock band, if you can believe it.
After college, I became a teacher, and was quite happy with the idea of doing that the rest of my life. However, I read a lot of mystery books in my spare time, and when my wife and I moved to San Francisco, I started missing Texas.
I decided, on a lark, that I would try writing a standard hard-boiled private eye novel set in my hometown of San Antonio. Ten months later, BIG RED TEQUILA was finished.
The strange thing is, I had a feeling that BIG RED TEQUILA was going to get published. It just felt different than anything else I'd ever written, because the novel had practically forced me to write it. The idea took me by the throat and wouldn't let me go until the manuscript was done.
I tell aspiring writers that you have to find what you MUST write. When you find it, you will know, because the subject matter won't let you go. It's not enough to write simply because you think it would be neat to be published. You have to be compelled to write. If you're not, nothing else that you do matters.
For me, that meant getting away from home for a while and learning to appreciate what I knew, before I could follow the old axiom, "Write about what you know."