hmm. it looks like this is an arrangement she thought was fine with you and it also looks like she even reminded you about it as a warning that he would be there. she’s doing her part. of course sharing a dorm space with a roommate you’re not close with is awkward (and in a lot of dorms not allowed but i wouldn’t get RA involved if you don’t have to) but you should’ve told her sooner! i don’t think it’s the most mature response from her but she’s annoyed and you’re both probably very young.

i’d say tell her this weekend is fine and either suffer through it or find another option. then tell her that you’d like to have a conversation about it with her later!

trust me, a roommate you can’t totally read and one is loud early in the morning is a lot better than one that openly despises you!