One of the challenges of thinking, talking and writing about children's literature is avoiding the trap of assuming you know the 'child.' All children are different. You can't define children by their age. Class, gender, ethnicity, education etc all have an impact, just as they do upon adults. Indeed, personal likes and dislikes have as much to do with which child is ready for which book as they do with which book an adult will choose to read next. The argument for age-banding books has met with great opposition, including from authors like Philip Pullman. Personally, if there were age-banding, I'd like to see it extended: "this book is only suitable for 30-35 year olds" or "this book is only suitable for 96 year olds." I'd be tempted to age-band Persuasion, for instance, for "29 year olds and above."
Remember your primary school days? How many of us had to fight a teacher or librarian to get access to a book judged 'too old' for us? How many of our mothers charged up to the school to demand we could read a book? The problem is, while guidelines can be useful for teachers and others who are faced with purchasing a book for a child, they often turn into the 'law.'
So I smiled when Neil Gaiman came up with a mushroom response to this trap. Indeed, it all depends on the child. And don't forget that some children do like to be scared.