AITAH for doing laundry?

My brother proposed to his fiancée last year, and after they couldn’t find an affordable house, my parents let them move into our basement. We have a big family—eight people and two dogs—so my parents had to rearrange the entire house, move their own bedroom, and put a lot of things into storage just to make space for them, all without a single complaint.

Lately, my brother’s fiancée has been making up rules for everyone in our house. On top of that, she’s extremely disrespectful of our space—leaving dirty dishes out when she cooks, keeping every single light on (including separate lights for her 30+ plants), and blaming her forgetfulness on her mental health. One of her rules is that no one can do laundry past 10 PM because she “can’t sleep” with the sound. Instead of telling us directly, she made my brother send the rule in our family group chat. My mom had already told them that this might not always be possible since we all have work, school, and other responsibilities.

I work late and am a full-time biology student with at least two hours of homework most nights. One night, I got home at 6:30 PM, ate, and put a load in the washer before starting my homework at 8 PM. I finished around 9:45 PM and went downstairs to switch my laundry to the dryer. My brother came out of his room to remind me about their “rule.” I told him this was the only time I had, and if I needed to do laundry, I was going to do it. He tried to argue, but I left it at that. Then, he texted the family chat (with her in it) reminding everyone of their laundry rule. I repeated what I told him before, and my mom backed me up, pointing out that I had started my laundry at 8 PM.

His fiancée then replied, “I just can’t sleep while the dryer is running… she just started the dryer right now,” as if it was my fault. I told her I rarely do laundry this late, but if I have to, I will. She responded with, “I get it. I’m just trying to figure out what to do bc I have an exam 🥲,” which irritated me even more. Like, close your eyes? Count sheep? I don’t care. I told her I’m not waking up at the crack of dawn to do laundry when I have class at 8 AM.

My mom tried to keep the peace by putting towels in the dryer to muffle the sound, and I thought the situation was over. But a few minutes later, my sister texted me saying my brother’s fiancée had left the house to go sit in her car because she “couldn’t sleep” and needed “privacy.” I found this extremely childish—she could’ve just tried to sleep.

I went downstairs to wait for my laundry so I could grab it before the dryer’s end-cycle song played. She eventually walked back inside, saw me, and silently walked past me down to the basement. My brother didn’t push it any further because he knows I’m not going to follow her ridiculous rules, but I could tell he was mad.

My mom later called me and agreed with me but told me not to argue with them (which I didn’t). Am I the asshole for refusing to let her make up rules in my own house?