Answer:
Its kinda funny I read this book in 5th Grade
Stargirl and Leo break up in the book "Stargirl" by Jerry Spinelli due to social pressures and the desire for conformity. Stargirl is an eccentric and unique individual, and her behavior sets her apart from the rest of the high school students. Leo, initially enchanted by her nonconformity, faces challenges as Stargirl's unconventional behavior attracts negative attention and judgments from their peers. In an attempt to fit in and conform to societal expectations, Leo distances himself from Stargirl, leading to their breakup. It reflects the theme of societal norms and the struggle for individuality in the face of conformity.