alpha girl
n. The dominant member in a group of girls; a girl who bullies other girls.
Citing new research on teenage relational aggression, a flurry of articles and books have appeared in recent weeks trumpeting the existence of the Alpha Girl (a k a the "really mean girl" or the "queen bee"), a supremely confident, domineering and manipulative teenager, whose main appeal seems to be her stereotypically masculine behavior.
—Emily Eakin, “Listening for the Voices of Women,” The New York Times, March 30, 2002
1994 (earliest)
Archer managed to overcome her father's misgivings by promising that he would allow Mary — an archetypal Alpha girl who duly collected an Oxford First — to follow any career she chose.
—Graham Turner, “The Midas Touch,” Sunday Telegraph, May 01, 1994