This seems to be a common denominator for all avid readers (and highly intelligent people). They were encouraged to read from an early age by their parents and had no restrictions on what they could read.
My own parents never believed I was "too young" to read something. If I was able to read it, then I was able to absorb it, understand it and put it in the proper context.
Like you, if I found something I liked, I endeavored to read everything by that author. I remember reading Jack London's "Call Of The Wild" in fourth grade. Within a year of that, I had read everything that Jack London wrote, including "John Barleycorn" and "People of the Abyss" - which was heady reading for a 4th grader.
Dickens, Twain, W.S. Gilbert, and James Fenimore Cooper were my 3rd & 4th grade authors of choice for me. It was in the 4th grade that I found Robert Heinlein, which got me hooked on Sci-Fi.