Describe symbolism in The It Girl by Cecily Von Ziegesar

Jenny's acceptance onto the varsity field hockey team, despite her age and her grade, are also symbolic for the emerging acceptance by both Brett and Callie, despite her age and her grade. The acceptance from Brett comes as sort of grudging respect for Jenny's genuineness, and the respect from Callie is emerging as a result of Jenny's potential utilitarian understanding of Callie's situation, and what she gains to benefit as a result because of it