Well, if you would like a piano teacher's advice (Suzuki method). I would not have a student perform in a recital until that person felt comfortable with the piece. If a child has nightmarish experiences performing, they will stay with her and she will eventually not like performing. Some kids start to dislike piano if filled with too many negative experiences. Some even start to dislike music in general. Less than positive performance experiences may also affect a child's self-confindence in a public speaking situation or anything else she may need to do in front of an audience in the future.
On the other hand, positive performance experiences help a child in so many different ways expecially with self-confindence and a love of music.:001_smile: