I've always made up stories in my head. See an object, make up a story about how it got there. That's me. When I was a kid, I wrote those stories down - I still remember using string and three-ring binder paper to put together books.
I stopped writing stories when I entered high school - too many academic papers to write, instead. I was 31 before I started writing again - as a blogger, and 32 before I started writing the stuff in my head. Now, most of the stuff is a bit X-rated. Ha!