Kostic played at OSU from 1992 to 1996, and led the Beavers to three consecutive NCAA playoff appearances in 1994, 1995 and 1996. Kostic was twice named Pac-10 player of the year (1995 and 1996), was All-Conference all four years, and was a consensus All-American in 1996. She was the Pac-10 player of the week on eight occasions, more than any other player, and was inducted into the OSU Athletic Hall of Fame in 2005. She is the current OSU recordholder for career points (2,349) and rebounds (1,001). After leaving OSU, Kostic played professionally in the ABL and WNBA as well as overseas.