Back in the day, I read the Berenstein Bears more times than I wished (my wish would have been zero times), to my kids who are probably about the same age as you.
It was such a relief when I could start reading them the Narnia Chronicles, and much later Lord of the Rings.
I've always thought it seemed early, but in my first grade class we read The Lion, the Witch, and the Wardrobe aloud as a group.
I don't really remember us having much trouble. I was hooked, and I read the whole series by third grade. I had trouble finding a couple of them, which held me up.
I got into many other books those years. My Friend Flicka, Black Beauty. The Hobbit. White Fang, Hatchet. The Forest Runners. Where the Red Fern Grows.
Still some of my favorites on that list. They really shaped my life, actually.
*Berenstain, but you're not alone: https://en.wikipedia.org/wiki/Berenstain_Bears#Name_discrepa...
Surely you mean the Berenstain Bears. --Just a shout out from the alternate universe before we split off.