Eleven seconds is the benchmark that separates the women from the girls in the 100 meters. Last Saturday, at the Brooks PR Invitational in Seattle, 16-year-old Candace Hill joined the elite group with a scorching win in 10.98 seconds, becoming the first U.S. high school girl to break the 11-second barrier, smashing the American junior and world youth records. Candace, who finished her sophomore year at Rockdale County High in Conyers, Ga., last month, is a five-time national champion, and already held Georgia state records in the 100- and 200-meter dash. Her record-setting race would have earned third place at this year's NCAA championships and tied for 10th best in the world this season.