Band can be extremely loud and she is learning one of the quietest of the instruments. While girls at this age grade5 to 8 are at their most difficult according to educators, boys are still just noys and love to make a racket. To add to her anxiety she is just learning the instrument. Like her I cant stand loud noises when i am attempting to learn something new or at many other times i find them aggravating.
Recently I spent the summer learning a major piece of music “Mozarts Requiem” with 70 other voices in a choir. Many had sung it before but not me. Normally i can pick something up (base Part) with very little effort but this was an 80 to hundred page terror. With no two parts singing together except the closing bar? Despite 50 years of singing choral music this was a brute. I was totally intimidated by those who already new it. And uneasy but i muddled through with a few hours work each week. Thankfully the director kept the instruments we were to sing with away and prepared us for how difficult it might be with them sharing the stage. They brought in the Orchestra before our dress rehearsal and I was totally thrown again. It is extremely hard to remember all you have just learned with the loud sounds of an orchestra in your ear . Trust me on this.
Also this was described to me by educators as the meanest stage of girls childhood education. I suspect your daughter may be a victim or just reacting to the changes.
Please check with her teachers and other professionals.