The Grumpus Among Us by Sharon R. Miller

Every family has one: a grumpus. Little Gracie is the grumpus of her family. Why, you may ask? Because her big brother, Tommy, likes to rile her up. And when he does, Gracie erupts! He teases her endlessly, about her wild mismatched clothes and pointed pinkie toe. But Gracie...

Gracie isn't about to put up with Tommy's shenanigans. While she lives up to the whole "fiery redhead" persona, Gracie is becoming accomplished at putting her foot down and standing her ground. She is who she is, she's completely herself.