Very nice job! One of the things I really like about this piece in particular is that you did an upwards shot, but I would in no way call this a 'crotch shot'. You get the feeling not so much of just looking up, but that she's standing strong and towering over her victims. It has a very intimidating vibe and really makes her feel like a threat, not just sexy.
Many people misunderstand that aspect of her character. She chickened out after her first kill, she was too young to understand at the time. She tries to distance herself from her upbringing as an assassin, to atone for her actions. Batman, while aware that she was bred for it, didn't know she'd already killed. It floored him when he found out, but she has more than proven herself to him.