Holly Black did a great job presenting Zach, Poppy, and Alice as such relatable characters in their move from childhood to the teen years.
The best part about Doll Bones is that this story is so much deeper than it seems. This story about a group of kids being haunted by a ghost turns more into a coming of age book. As the story progresses, you see the actual hardships haunting these children.
I would stay with the recommended age group of 10-12. It has a quick pace to keep a younger readers' attention, but it IS 250 pages.