After it was confirmed to her that it couldn't hurt her, Presley was eager to step infront of the dummy and try her spell. She pulled her wand out of her pocket, and waited for the jet of light. "Protego!" she said, and failed. The light hit her, and she stepped out of the way, letting other students take their turns. Protego, Protego, Protego!" she practiced by herself. Maybe she had the wand movement wrong?