The first book I read for real was Billy Brown the Baby Sitter. I remember reading it and being a little shocked that I actually read the whole thing. (It might have been aloud or it might have been silently). I think I was 5 or 6 and the book was a “Wonder Books Easy Reader” book. I have it in the house somewhere and may have written about it on another blog. I don’t remember much about the book except that Billy Brown was likely an unreliable babysitter.
I feel like maybe I read this at some point. But not to be confused with Encyclopedia Brown!