Worried about development of 10 mt old.?

It sounds like he is fine, he just doesn't like different textures like the gr. As for the being a super picky eater, I have never met a child who was not a super picky eater. My daughter went through a phase where she would only eat potatoes. Mashed potatoes, baked potatoes, french fries, potatoes in eggs (basically anything with potato in it). It got to the point where my husband and I could not stand the sight of a potato. The book thing is cute. My son has a favorite book, The Moon in my Room, and turns to the exact page he wants read all the time. Your son is probably just fond of the particular part of the story. I think your son sounds like a healthy child who is just trying to express himself the only way he knows how. Enjoy him and his little quirks, they grow up so fast.