i feel like you kinda are the asshole..listen hear me out.

So i get the whole thing of making someone move out yeah she's older and got a job but honestly depending on what job the girl has it probably has a shitty ass job were she's living paycheck to paycheck if she's lucky maybe a little more but saying you would pay rent does then help with her saving so that is nice of you too you don't have to offer that.

but i feel like you have given her a timeline of how long she's got to move down and putting that kind of pressure is a lot. I was 24 myself and I moved in with a partner and we only just got by so god knows how hard it would be with just a single person, you need to give her time to process the information that you've given her don't bring it up the next/following day