From my limited understanding, it is more important at younger ages to develop proper mechanics, arm strength, and muscle memory - this is not something that happens in a few months, but may take a year or more. Once they have command (can throw to location for strike and non-strike), a new pitch makes sense. In 10U ball last year with my daughter, the most successful pitchers threw fastball/change, mostly fastball. The few drop-curves they saw were almost never strikes.
A new girl (11 yo) on my dd's team currently has been in lessons for 4 months and throws a fastball, change, screwball, and drop curve - none for strikes. My dd's PC says it will take another PC many more months to undo the damage that is being done now, because the (flawed) mechanics from her "screwball" or "drop curve" will inevitably bleed into her mechanics for her (flawed) fastball, and she won't get any faster or have better command until that happens.
Be patient, be glad your daughter loves to pitch, and be glad that the two of you will have some great memories when she is older.
A new girl (11 yo) on my dd's team currently has been in lessons for 4 months and throws a fastball, change, screwball, and drop curve - none for strikes. My dd's PC says it will take another PC many more months to undo the damage that is being done now, because the (flawed) mechanics from her "screwball" or "drop curve" will inevitably bleed into her mechanics for her (flawed) fastball, and she won't get any faster or have better command until that happens.
Be patient, be glad your daughter loves to pitch, and be glad that the two of you will have some great memories when she is older.