Chang made her Olympic debut, as South Korea's youngest swimmer (aged 14), at the 2000 Summer Olympics in Sydney. There, she failed to advance into the semifinals in any of her individual events, finishing fortieth in the 100 m freestyle (58.77), and forty-first in the 50 m freestyle (26.88). She also placed seventeenth, as a member of the South Korean team, in the 4 × 100 m medley relay (4:16.93).