I grew up in a family of readers, with a houseful of books. I can't remember a time when I couldn't read, but my mother told me that she used to read aloud to me, until one day I said, "I'd like to try that." That was before I started school, and I can remember a teacher "showing me off" to the elementary school principal because I could read aloud from the newspaper in kindergarten.
I always think it's a good thing I started reading early--there are so many books I want to read, and never enough time. (And they're always printing more!