You looked really good for your first show! Your horse was also adorable!
Anyway, I noticed over many of the fences that you didn't jump over the center of the jump; you tended to drift to the right side of the jump. In the future, use a bit of right leg and left rein to correct this problem. Also keep in mind that, while your horse's head may seem like it is pointed in the correct direction, his butt isn't always in the right place. In several instances, especially after turns, his butt had swung way out to the side, but his head was pointed at the jump, making for a few awkward jumps. Again, try to use your leg to correct this problem so that his head and butt are lined up with the butt.
Additionally, try not to let the horse rush the fences. That made for some strange distances to the fences. By keeping him collected, you can plan ahead for a better distance to the jump.
And lastly, it looked like you were just standing up in your stirrups when you went over the jumps. Try to bend forward further at the hips and give a bit more of a release.
Overall, you rode really well. Keep it up!