It's My Party (1)

On Jen's birthday, she is unusually un-eager for the usual party ingredients, clearly only pretends to appreciate the hand-puppet show dad revels in, and actually gets completely obsessed with imitating the fashion-obsessed herd of 'cool kids' at school, even if that means abandoning all her rather tomcat habits. Stacie's gang and chasing boys seem to overtake her whole personality, she even takes lessons in 'cool' signals and talk from airhead Mallory.