I could be mistaken, but my impression is that Rowling adopted an attitude that the kids who started with her first book, had matured into teenagers and this was her audience.
That's true. The problem as I see it is that parents are letting their very young children see the final movies in the series now that all the movies are out (i.e. the parents who are not familiar with Harry Potter don't realize that the last few Harry Potter movies are not really age appropriate for young children. They base everything off of the first movie).