Re: "Are you there God, it's me Margaret..." for an 8 yr old?
I'm not really a fan of censorship when it comes to books unless they're graphic novels or um, well, just graphic (Anne Rice's Beauty series, for example, will not be available in the house).
If she was bored with it she would have put it down, and it's good advice for her age anyhow. It's a pretty tame story. And it would be a great opportunity to talk to her about menstruation and even giggle about the devices poor Margaret and her friends used to use. There's even a whole 'museum' online devoted to this subject - http://www.mum.org/belts.htm
Left DS because of lack of virus control.