The student pilot reported that the en route flight conditions of his solo cross-country flight were smooth and the arrival airport traffic pattern was normal. On final approach, a strong windshear pushed the nose of the airplane down when he was approximately 100 feet above ground level, and about 300 feet from the threshold of runway 13. He reduced power and pulled back on the control yoke. The main landing gear impacted sandy soil prior to the runway surface, followed by the nose gear, which dug into the ground and caused the airplane to nose over. The airplane received substantial damage to both wing spars, the firewall, the left elevator, and the vertical stabilizer. The pilot did not report any preimpact mechanical malfunctions. He stated the winds were 120 degrees at 10 knots, gusting to 18 knots. The pilot reported 24 hours of total flight experience; of which, 7 hours were solo flight. During a postaccident interview, the pilot discovered he referenced the wrong scale on the airspeed indicator. The outer scale indicated airspeed in mph and the inner scale indicated airspeed in knots. He referenced the outer scale, labeled as mph, which he incorrectly thought was indicating knots.