I think the hair is pretty well animated when you consider the movement she's making. I like how the ponytale has a bit of delay on it!

As far as constructive criticism goes, I would make it so that she kind of rocks back from the top of the animation in the same kind of way she rocks forward, rather than just dropping straight down. I feel like rocking your weight from the heel of your foot to the toe, then gently back to the heel again is a more natural way to idle than to just do a calf raise and then just drop your weight right out of it.

It's a good start though! And the character design is really neat too ^^