When my then DD7 read the first book, she had nightmares about the Voldemort creature/character slithering through the forbidden forest (curiously she did not find the person with two faces disturbing). She's now 10 and has read many books that I would consider to be much scarier. She has no interest in reading HP to this day even though everyone in her class has read them multiple times. I wish that we had waited because I think she will miss out on a great series. For her, it would have been better to wait a year or two.