At about 1020 eastern time, a Cessna 152 was substantially damaged in a hard landing at Ormond Beach Airport. The student pilot, who was on her first unsupervised solo, was not injured. The pilot said she had flown the traffic pattern twice, and had made two uneventful landings. During preparations for her third landing, another pilot suggested on the Unicom frequency that all aircraft switch to a different runway. The student pilot said that switching runways in flight caused confusion for her. The airplane porpoised as she was executing the landing flare and touchdown of her third landing, and she was unable to gain control. The nose gear collapsed, the propeller contacted the runway, and firewall was damaged.