I think even 10 years can read it. Not difficult words, just lots going on to remember. Not really too bad either. The movies actually do the books well.
I no longer have the other books. They all sold on Listia. I love the Harry Potter stuff. It is just Good Versus Evil. taking place in the world of wizards. She is an amazing writer to have thought of all these things.
My daughter and I love the movies... Silly me, I had a set of 4 of the movies and sold them in a yard sale before I even saw them! Didn't really like the 1st one but then I saw the others and liked them... oh well! lol