Family Ties (1982)

S5E23 "D" is for Date

Jennifer experiences her first big crush on Tim Higgins, her science lab partner and the charming star pitcher of the school baseball team. When Tim visits to collaborate on their science project, Jennifer is excited yet flustered by his genuine praise for her academic skills. Concerned by the belief that boys are not attracted to girls who outshine them intellectually, she resolves to downplay her intelligence to keep Tim's interest alive.