After a number of dual circuits, the pilot was authorized to carry out solo circuits with touch and go landings. After the first touchdown the pilot applied full power then selected the flap to 10 degrees. The aircraft entered a rapid turn to the left, and the pilot abandoned the take-off. The aircraft slid sideways off the strip and the nosewheel was broken off. The pilot was carrying out her first solo period of touch and go landings. After applying full power she noticed that the aircraft was accelerating more quickly than when she had been under dual instruction. The pilot had previously required forward pressure on the control column while retrimming the aircraft. On this occasion she had not had time to retrim and the investigation revealed that the aircraft had been "wheelbarrowing" on the nosewheel when directional control was lost.