When I was in daycare (4 or maybe 3) I was really noisy, so the teacher, probably wanting a break, taught a few kids including me to read. The first word I wrote was Meow, although I think I wrote it Miau which is how you write it in Spanish. (I'm from Argentina; I lived in the US since I was 2 until I was 8, so English was my 2nd language but my 1st reading language. I learned reading in Spanish on my own, although when i moved back I rebelled and refused to write accents (árbol).)
It also helped that my mom read to me every night, pointing each word as she read it.
I remember that there were always scientific papers lying around the house, and sometimes I read parts from them (mostly just titles). As a consequence, when the 1st grade teacher asked for an A word, I said "Abstract!"
I love reading the thesaurus. My edition explains words in a really interesting way; for instance, "gay" (the happy meaning) is "Stresses complete freedom from care and exuberantly overflowing spirits".