Not bad. I hope you rewarded your sister; beyond the call of sisterly duty
Lecture: When it is cold, you need to warm up more!
I liked your follow through very much; generally, this is a very strong side on action.
Just two things I would change now:
At the point where both arms are above your head, you really do need to keep your hands within peripheral vision.
It is very important that you correct your counter rotation. As your non-bowling arm comes down, keep your elbow tucked in so that your forearm travels down more or less vertically. You MUST be looking to the left of this forearm, which pushes your shoulder more to the right. However, keep momentum travelling forward in a straight line as you have it now; don't be tempted to rotate too much. If you continue as you are, you risk stress fractures of the pars interaticularis of the lumbar spine.
At this angle, I cannot see if there is any excessive hyperextension but it looks good.