The solo student pilot reported that during the landing roll, she was not ready to turn off the runway when the tower controller instructed her to exit the runway at taxiway "C". The pilot tried to follow the controller's instruction and made a turn at the taxiway. During the turn, the left wing was substantially damaged when it struck a taxiway sign.
The pilot reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation.