MAN! If they used your concept supergirl in the sequal of man of steel for design purposes, that would be so awesome!!! I love this picture so much I want a big poster to hang in my room next to all my other superhero posters.
I don't know why, but she looks very vulnerable. It must be her kiddy like style face and her stance of her overall and her fist saying "I'll punch you." Which would come across in a high pitch feminine voice. I do love your style though!