Amanda Jones I think there's a complexity to it which young teens may not be ready to understand. They might be impatient with the plot whereas a more mature reader is curious about who these people really are and what really happened. I might be entirely wrong here.
This answer contains spoilers… (view spoiler)[Probably not. Many of the neighbours' secrets involve abuse of some kind. It's more often hinted at and there's nothing graphic, but between that and Ms Dakin's backroom abortion, I'd say wait a few more years until they're an older teenager. (hide spoiler)]