Although Hingis wears braces, giggles and just started eighth grade, she already has commercial endorsement deals for clothes, shoes and racquets. In 1996, the minimum age for going pro will be raised to 16, so that girls like Hingis won’t face the kind of pressure that has bedeviled Jennifer Capriati. But Hingis isn’t worried, she told a newspaper reporter. “I think that the pressure on the players in Europe is not as big.” Maybe.