You ought to get her a rusty one, they don't make as much noise.

Yay! Wait. What?! Oh rats. Yeah. Sorry.

Uh... Get over it?

This situation really blows.

Wah-wah-wahhhhhhhh.

Yeah it sucks for a little while but there is a mute she can buy for the trombone to make it quieter than what it is and also once she practices a little bit, she'll probably be pretty decent. Just tough it out for a little while (unless she's being rude and won't let you sleep or something) and it should get better. :)

OP isn't demanding that she stop. Just saying it's a little miserable to have to listen to any instrument being played poorly. Calm down.

What's wrong with trombones? My friend practicing trombone always sounds better than my practicing of clarinet — we both play well (first chair), but the lower, smooth sound of the trombone isn't horrendous even when messed up. My high notes will kill ears even when played properly, because they're so high. Also, she may not even really make noise at first because it can take time to build lung capacity.

So?

When I got to 6th grade I joined Band and got a Flute to play. I never practiced at home. Not even once. I learned and practiced during class and was always first chair. It depends on the situation but I didn't want to bother anyone at home. If she's in a daily class maybe she will get lots of practice in and get good soon.