The inevitable question comes up in interviews and book talks. I generally answer age ten or eleven. However I now have proof it started much earlier.
I was five when this photo was taken. For those too young to know, I'm at a typewriter...the original word processor. You had to have a special eraser to fix your mistakes. Strictly manual.
So, now I can tell people the idea of writing came to me before I started school. Although I must admit I probably could not have told you what a sentence was. I was well aware of books as my parents read to me from an early age.
Now the question has been answered.