This fiction book will appeal primarily  to female readers between the ages of 3rd-5th grade.  Young readers who enjoy books with visuals, such as different font, occassional cartoon picture,  illustration, diagram, etc. will appreciate the format of this book.  The plot of the story is based on friendship and self confidence.  Grace’s best friend Mimi is going to become a big sister.  The girls want to practice being a family helper with caretaking of neighbor children, but the plan backfires as the young charge seemingly prefers Grace over Mimi.  This undermine’s Mimi’s confidence in becoming a good bit sister.  The girls work together for a happy ending to this story.  Blooming chapter book readers might enjoy the format of this book.