Overexposed too much light hitting the camera. Lower the ISO setting on your camera. If it was on auto, try playing around with the manual settings. Was it taken in portrait mode?
think this might have been stronger if you were farther away from the light in front of you(?) to creat a deeper silohuette. currently a bit washed out. perhaps some play with the levels and contrast would have helped. and raise that right arm a couple more degrees!! :oP
I think this would have been a lot more effective a picture and challenge entry if you had cropped to form a right angle in the silhouette and lose the bright background at the bottom and on the left.