I recommend trying to create a better balance of load + power and with quickness in your delivery . I saw in that video you were pitching in the stretch and I believe I saw runners on base. Many kids try to get rid of the ball as fast as they can because they are worried about runners stealing on them. However, this is pointless if you get no power in your pitch (which could be from not loading). I recommend trying to load with your back leg and hip a little more and then driving with your hip as 4pie said. I also recommend keeping your hips closed a little longer because you're turning your chest and hips too soon to the plate which causes you to lose power. As I finish here I'll have to congratulate you. 5 innings with 1 ER is impressive especially for someone your age.