Ideally, two partners will try to find a collaborative solution to differences. If that doesn't work, cooperation is next. It sounds like she tried a nominal cooperation offer then went straight to an ultimatum, which is a competitive style.

I second the redditor who recommended couples counseling. This is for surround sound but what else does she expect to have total control over?

Please, be very careful to not make any babies until you confirm that she is a kind, generous partner who can cooperate with you when collaboration isn't possible.

Moving in together amplifies problems in a relationship. Getting married and having babies do, too. Sadly, many people will do these things when they are trying to ignore or "fix" problems in a relationship. Just in case the surround sound problem isn't a one-off, just want you to be prepared to see other potential problems. Please, if there are more signs she cares more about how her life looks than what you want, run. If this is a rare and weird occurrence for her, ask her to at least sit down and try to collaborate with you.

Good luck!!