Even though the piece is very minimal in it's appearance, that's where it's greatest strength lies.
The color white has always been associated with purity, innocence and frailty, so to give the model such a porcelain complexion, surrounded in an almost blindly pure white haze, it automatically speaks so much, so quickly.
Juxtapose this purity with such a powerful but unflinching gaze, allowing the viewer to decide if she truly is innocent or plotting something that you're powerless to prevent.
The deciding factor on being the upside down cross or simply a division of the face. Was she deemed evil by others or herself?
The image, while minimal can speak so loudly depending on how you view the world, innocence accused of evil, or evil hiding within innocence.
Sometimes the smallest things say the most. Love the symbolism. What's interesting, though, is that the upside down cross is also known as Saint Peter's Cross. Simon Peter, according to Catholic tradition was crucified upside down. It became an anti-Christian symbol more so in recent times. What I like most about this picture is what you've already stated. It can be looked at in so many ways. Does the person, herself, see herself as pure and the world doesn't or does the world see her as pure and she doesn't? Such a tease on the mind. Great idea, here. Kudos.