The pilot was attempting to complete a solo flight of at least one hour duration as part of the qualification for the issue of a C Gliding Certificate. Witnesses reported that during the winch launch, the glider lifted off too early, and then assumed the climb attitude before sufficient airspeed had been obtained. The pilot stated that she released from the winch cable when she became aware that the airspeed was too low. At about the same time the right wing dropped and the aircraft turned through about one and a half revolutions before impacting the ground with the right wingtip. The pilot had attempted to correct for the wing drop with aileron control inputs, which were ineffective at the low airspeed.