Room with glass windows as a walls.

to you it was because you know all the background info. 

to me it wasn't

based on the responses and questions, it wasn't 

but it's your post, apparently you think you are absolutely right, it makes no sense to argue

I have (had) a similar problem with a wall of glass paneled doors with windows opposite my speakers , in back of my listening position. I had custom Draperies made with a think cotton front with heavy liner or backing behind and attached to the front fabric. The drapes are weighty and folded and provide fantastic absorption because there are many folds as well as thick fabric. So basically the sound gets sucked in and can’t bounce out. The room might even border on too damped. So any further room treatments are on the side walls  I have used diffusion. I have a thick fabric couch with a padded area rug.   The diffusion on the side walls at the 1st reflections and behind the speakers on the front wall , allow my system to shine. The room seems much larger with the diffusion. Do not over damp with absorption!! 

These are black-out drapes for the projector. They have a double layer and do a good job of diffusing the sound and removing the window reflections and vibrations.

Directional horn loaded speakers w/ warm tube amp could help. Volti Razz? 

I have a daughter who is a professional musician. 

She is also a fashion trendsetter. 

She has never been interested in my advice. 

I suspect that though your daughter may be neither of these things, she is moving into a new apartment, signaling her independence.

Don’t be a helicopter dad. I'm guessing she will figure it out.