That look on her face is adorable! I see a little Tophitude in there, same happy "I'm'a kick yo'ass, sucka!" expression. And yet the face (and especially the eyes) remind me more of Suki. Very pretty. ^.^
I know you're likely not the one who designed the outfit, but I have to give you props for how you worked with all those creases and folds in the costume. Look at all that linework and all that shadow detailing on the skirt! Man, that's hard to get right; I'm envious...
Very animate pose, very solid and earthbender-like stance. It looks very natural and all the proper muscles appear to be in the right place. Lovely!
Only critique I have is her right foot. A neat little trick I found out (or blatantly stole from spiderman's artists [link]) is to make the foot wider around the toe area. It helps to make the foot look more grounded and not like they're floating into space like mine used to do.
That being said, drawing feet is the absolute pits. I still try to hide mine whenever possible.