You hit OK. Turn you shoulders sideways more to get some power in your shots.
Your serve is fine for the amount of effort you put in. Notice you don't jump forwards or upwards, so you get what you put in.
Nice 3.5 level shots. You lose because most high school players are 4.0+, so he's just better than you.
When you hit a ball machine, don't just hit the ball back over the net, aim for specific spots and don't hit up the middle.