Most pitchers, even at the varsity level, can get by without a curveball in high school -- IF you've got a good change up. I'd keep working your fastballs and change up. I'd scrap the curve for now, unless you feel you really need it. But I didn't throw one in high school ball, and I was a starting pitcher on my varsity team as a freshman (6-0). The more you can work on and develop the fastball in your youth, the longer career you'll have. Period.