pitch selection

You throw what the coach tells you to throw.
No questions at your age, Just Do??
Of course your the one pitching, But the coach may know the batter's weaknesses.
So do what they say.
Work on locating the pitch that the coach calls for.
EH

When I coached JV ball, freshman pitchers couldn't throw a curveball until they showed me they had good command of a fastball and change-up.

Amen Larry. Simple, easy to understand answer that all young pitchers should grasp. Learn to locate. Learn to play catch with a change-up grip.

Just a FYI post this in the pitching section next time.

Our HS coach requires pitchers at the beginning of the season to only throw fastballs. Once they get command and can get guys out with them they move on to ONE more pitch. Once they get command they are allowed to add a third. BTW a "fastball" can be thrown a different speeds and locations. Try it some time you will be surprised at the results.

And by changing how you grip the ball, 2 seam --4 seam--you can make the ball move differently