Stop action, looks like you'd have a sore tired back at the end of the day. You look abit stiff or tentative in the upper body...seems like you aren't comfortable going that fast thus "bending over to get lower" instead of crouching. And your hips are abit rotated open with what looks to be a slight duck stance on the rear foot...it seems you almost have an alpine carver open hips. I think if you straightened your back and closed the hips you would be less counter-balanced on top and then be able to really snap some cross-under turns. But great job for only being 3 years into it.
edit: perhaps you hips are doing ok...but work those hips and knees and lower body more...get them really working...they could be more dynamic or loose...you are going fast enough to really power some carves or snap some cross unders...maybe think about moving fore and aft along the board in your turns. Your upper body is too stiff...you need quiet but not stiff. Straighten your back and relax your arms by the side