My only problem with this image was for the challenge requirements - not really sure she could not be an adult. If there was some other element on her clothing perhaps that indicated youth or more of her face which I assume looks young were showing might have made this a stronger image.
I love the stark contrast but there is just too much reliance on the title to convey the idea of adulthood, the image looks very unrealistic and it's hard to tell if the person is a young kid, teenager or an adult.