I know that a lot of girls play junior volleyball. Now my daughter's coach wants her to play. My daughter goes to a small school and plays a sport each season. She's probably going to start every year on her volleyball team. Why play on a junior team? Is it really worth the expense? The travel? Having to deal with all the new people? The headache of driving far away to practice?
The answer to this question is simple: How good does your daughter want to be?
Option No.1: Good Enough
Does she want to be "good enough"? It sounds like she already is. From what you describe, she can be a star on her school team without doing any more than she already does. And if that's all she wants to be, then that's fine.
But her school coach might be seeing some untapped potential in your daughter. He may also have some team motives as well: more wins, a championships, etc.
Your daughter may choose to attend a few summer camps and do some conditioning. That's normal for the "good enough" crowd, and they usually convince themselves that camps and conditioning are all that's needed to reach their potential.
Some girls go to small schools, so they see no need in playing juniors. They believe that spending a hundred hours in the off-season on volleyball will allow them to reach their potential.
But what I've described isn't even close to what the best players sacrifice. Please tell your daughter that these activities will not take her, nor her teammates, beyond "good enough". No, they won't. If she thinks they will, she's wrong.
But is she committing a sin just wanting to be good enough? No, of course not. The majority of us are only good enough in the majority of our activities.
We could eat healthier, exercise more, take care of our cars better, make better grades, keep the house cleaner, etc. It's OK. No need to worry about. Being "good enough" in the majority of our activities is normal for us Americans.