Here's why:
* Themes and content: The movie contains some violence, peril, and suspense that might be too intense for younger viewers.
* Reading level: The movie is based on the first book in a series, and while the movie simplifies some aspects, the source material has a reading level appropriate for ages 10 and up.
* Personal preference: Ultimately, the decision of whether or not a child is ready to watch *Percy Jackson & The Lightning Thief* depends on the individual child's maturity and sensitivity.
It's always a good idea to preview the movie yourself or with your child to determine if it's appropriate for them.