Am I riding this horse well ? *Sitting trot / riding Critique please*

It was hard for me to see much because of the quality and also because my computerwas making it slow.

To me, it looks as if you have your head down a lot while you're riding. Keep it up and look where you're going. Not at the ground. Your toes should be pointed up, heels down to help put weight into your stirrups and keep you balanced.

Also, try drawing your legs underneath you a bit more. There is a line that you should have, which extends from your shoulders, knees, and heels. All should be in line with each other.

^^ I think you mean shoulders hips heels !

The only thing that really stood out to me was that you were looking down a lot.
Apart from that you were sitting it nicely! As my instructor would say, "hips! Hips! Hips!"