J.B.
Definitely read the book first -and have the child read it. If the child isn't old enough for the book or to comprehend the book or read it fairly quickly (it's a FAST read even for a kid), then they probably aren't old enough for the movie. I know a number of 10 year olds who saw it and loved it -but they've already read (and can converse about) all three books in the trilogy. My two are still too young to read or see it, but I can see my oldest being ready for it at 10 or 11. It's specifically for the middle school-aged crowd if that helps. I certainly wouldn't dip below age 10.