Steven Van de Velde, the Dutch beach volleyball player who was convicted in 2016 of having sex with a 12-year-old girl in England, will make his Olympic debut Sunday when he and teammate Matthew Immers meet Italy on the sand at the Eiffel Tower Stadium. “If an athlete or a staff member had that conviction, they wouldn’t be allowed to be a member of our team,” the head of Australia’s delegation, Anna Meares, said this week. “We do have a number of athletes under 18 and under 16 and so those policies are well in action for safeguarding of our team.” Now 29, Van de Velde was sentenced to four yea…