I must say...

and I've said it before, but I'll say it again, I wouldn't want grow up again.  Growing up is ROUGH STUFF!  Whoever looks at kids, or tweens or teens and thinks, "Man, it would be great to be young again, their lives are so carefree!"  is totally wrong.  I guess every stage of life has it's challenges, but when I read tween novels, I think tween time must be among the hardest of times.
Figuring out self, figuring out friends, school, family.  And everyone is trying to figure it out at the same time.  So some kids lash out at others, and other kids are the victims and some kids are do both at the same time, but no one has it easy.  I love books like this, where the characters are complex, there are no "heroes" or "villains" everyone is a bit of both, just the way it is in real life.
Oh well...that's not true for every tween, of course, certainly not Margaret Simon and her evil friends.  But it is true of people in the real world and the characters in The Kind of Friends We Used to Be.  Kate and Marilyn have been best friends for a long time, but now in seventh grade, they are drifting apart as each girl tries to figure out who she is.
Yes, the story has been told before, but every story has.   And this story is told very, very well.