No expert on young horses, but...
I think it depends how far up the levels and how competitive you want to be. I am certainly no expert in judging young horses but I agree with some of the previous comments:
* Her neck is too short (but perhaps it will get longer as she grows?)
* Her shoulder is not very free in the video
* She seems to be a 'leg mover'-- not using her back much
However, dressage allows you to improve a horse through training, so perhaps some of these things could be improved with the right training.