Why did Stargirl leave Mica High School?

Stargirl left Mica High School because she felt that her uniqueness and individuality were stifled by the pressure to conform to social norms. After initially being embraced for her eccentricity, the negative backlash from her peers intensified, leading her to realize that she could no longer be herself in that environment. Ultimately, Stargirl chose to prioritize her authenticity over fitting in, which prompted her decision to leave the school.