I rated this movie ages 11+ because i think younger children would not really understand the story line or the meaning behind most of what occurs (no offense). it really depends on the child.
This movie looked so impressive from the trailer, and I must admit I was looking forward very much to watching it. But some of the lines were major letdowns. Hailee Steinfeld (Juliet) threw away so many of her lines, with some of them barely audible. She made the words sound just like sounds, there was little emotion or meaning to them. I know Shakespeare is generally difficult to connect with, but she really needed some of her lines explained to her.
Apart from this, I thought it was a great movie, and cried when (does this count as a spoiler? It is basis for the entire film...) Romeo was banished because it was so unfair. not to mention the ending.
I found the character portrayal was done well, with stellar acting. The scene where Romeo and Juliet umm ahem, is very minimal. literally she removed his shirt, he takes of her coat and they kiss on top of a doona. Even when you see them the next morning they are fully clothed. This makes it appropriate for younger kids because it would go straight over their heads.
Consider it a great movie and would recommend to see ASAP.