I like the advice I'm reading here! A dark-colored dress (either black or navy) that's at least knee-length or longer would be beautiful.
I also have to interject that, while sparkly and fun in some aspects, the shoes have an overt sexiness to them which bothers me a bit considering your age. I know you want to feel pretty and edgy and maybe just a bit shocking, because, let's face it, that's FUN! I like to do that myself; however I always keep in mind something my husband told me: a woman with a hint of sexiness to her is far more intriguing that one with it written all over her. Imagine this: a dress that covers the bust and legs, but is form-fitting, not tight; or a looser dress that is slightly sheer (only slightly--we want to *hint* not give everything away), etc. You can achieve this kind of thing with a modest dress and those edgy shoes.
How comfortable are you at standing out from a crowd? When I was your age, I wanted to blend in with everyone else, but now that I'm older, I love standing out--even if just a little bit. If I were going to a formal dance and all the other girls would be wearing shorter dresses, then that's exactly what I'd steer clear of. I would not want to look like everyone else! I'd pick something tea length or longer to stand out and make a statement.
Just food for thought! When you do find your dress, please let us see Have fun.