Sweet Thang by Allison Whittenberg.
Set in the seventies, this book features a loving black family and a strong black female protagonist.  Charmaine is a smart girl who is going through puberty.  She worries about the way she looks, longs after the handsome Demetrius, and hates having to look after her little cousin, Tracy John, after school.  Charmaine is under some pressure.  She has to deal with girls with lighter skin calling her names, Demetrius gives her attention in exchange for Charmaine doing his homework, and Tracy John simply will not listen.  Throughout the book, readers will understand Charmaine while still seeing the point of view of her larger family, which is quite an accomplishment.  The book is warm and inviting.  Reading it is like visiting family again no matter what color your skin is.  This is a lovely book that almost all middle school girls will enjoy.