I don't know. I started when I was 7 or 8. I always loved books about talking animals, so I wrote a story about animals. When I was 9, I had this idea for a story in a different world where certain people could shape-shift into one animal. Ever since then, the idea for a different world was almost in every story I thought of.
Also when I was 9, I kept this notebook. I carried it outside, looked up at the clouds, and drew something that had an interesting shape. With that, I created my own creatures. I even created my own language! I started writing at lease 3 stories with some of my creatures in them.

So that is my story of how I got into writing.

When i was little my cousins and i used to make up all kinds of stories when we played make believe. One time we called my Uncle the clownyman or something like that when he'd drive by in his dump-truck we'd hide.
One time we pretended we were dogs in boot camp and our counselor was Sgt. Duck.
Which i didn't start writing things down till i guess third grade. My stories fell under the same genre but they were based off of prompts so they'd occasionally feed off of stories and movies I'd seen. Lets see one prompt was about you woke up and found a castle outside. When i wrote on that prompt i wrote about Robin hood and the ruthless mamas boy king John. Another one i wrote was about a snow man i believe mine was named Frosty anyways. When my teacher read it they said that its a four paper if it wasn't that i had poor mechanics.
The field of Fiction has been my play ground from the early years and I'm still writing in the same genre but i try several others as well.