I (25F) live with my mother, whilst my sister (28F) currently lives with her boyfriend around 2 hours away and visits on average a few days every ~2-3 months. My sister was over for Christmas, and whilst I was joking to my mother about getting a pet cat, which she in the past has refused as she said its too upsetting when pets pass away, my mother agreed we could get one. I start to get excited but my sister said that we can’t get a cat because her boyfriend is allergic. I asked what does that have to with me getting a cat, as her boyfriend has only visited our house once in the 4 years they’ve been together, to which she replied that it would mean she would have to wash her clothes more. I countered that she’s not here that often and would probably visit even less since she’s set to attend a university over 4 hours away. Then she asked if I could afford the thousands of pounds to spend on a cat, followed by asking if Im aware of how much responsibility having a pet is and why do I even want a pet anyway.

At this point I was getting irritated, as its hardly as if having a pet is uncommon and she’s patronisingly questioning me as if I’m a child wanting their first pet, plus she is aware that I am more than financially stable enough for a pet and I am hardly an irresponsible adult - in any case more financially stable and responsible than her. I then ask why she has to be so negative, but she says she’s just asking a question, and when I say that she’s asked multiple patronising questions, she changes it to she’s just asking two or three questions and isn’t she allowed to do that? I say that its a two or three questions too many since it’s not her business, to which she says that Im trying to stop her from talking. I, upset by this point, say that she’s only been completely negative and its not like she’s had any positive thing to say about it. She asks why Im getting so emotional, and I exclaim that she’s rained on my parade, to which she looks at me as if Im crazy, and my mum breaks the argument by saying no one is getting a cat.

A few hours later after regrouping my thoughts I bring up the few times I’ve asked innocuous questions about my sisters personal life/relationship, and she’s immediately told me to drop it or that its not my business, so I do, whilst when its the other way round she keeps going, and that she interrogated me as if I said I’m having a baby. She says that it was just a joke and that she was on her period, explaining her emotional reaction, to which I ask if that really makes it fine since I was also on my period and personally don’t think it excuses my emotional reaction either, but she said yes it does, so I drop it.

This past weekend when meeting up with friends and their partners, one of them who I have told this story to before as she herself has cats and knew I wanted one, told me to explain the story to the group, who all seemed bewildered at my sister acting that way at her age. My sister was visiting yesterday and asked if she could wear my flip flops, which I refused and saw she was already wearing them. I, annoyed, ask why she would put them on before she had asked, to which she said she couldn’t remember if they were hers or not and forgot they were mine, which is something she has done since we were kids, whilst I’ve never been able to understand how you can’t remember if something is yours or not. I brought up the fact that I’ve had these shoes for over a decade yet she somehow thinks they may belong to her, and she said that they’re just flip flops and that I’m overreacting. I then brought up that when talking with my friends and coworkers they agreed with me that her boyfriend’s allergies shouldn’t affect me getting a cat since he doesn’t visit/live here and its not really her business since she’s not here much too, proving that I wasn’t overreacting over the cat argument either, however she asked if I told them that she said it was just a joke, and that her friends/boyfriends think the financial question was valid and that I am overreacting since she told me at the time that it was just a joke.

I am aware that this all sounds childish but I feel that saying that its a joke after the fact doesn’t negate the previous actions and I don’t see what part was supposed to be funny.

So, am I the asshole for getting upset that my sister questioned me so much over wanting a cat, or was it just a joke that I am overreacting to?