While Avoca Beach 's Macy Callaghan took down reigning World Junior Champ in Hawaii 's Mahina Maeda .
Avoca Beach 's Macy Callaghan at 16 has only just finished year ten .
While Avoca Beach 's Macy Callaghan , who at 16 has only just finished year ten , took down reigning World Junior Champ in Hawaii 's Mahina Maeda .