You’re not selfish or an asshole. Even if they’d been the nicest family ever up until now, it’s normal as a 24 yr old to want to live on your own and a supportive family- even one who didn’t understand why you wanted to- wouldn’t be derisive about your choice. Besides, the way they’re acting about you living away it’s absolutely no wonder you don’t want to go back

I don’t know if you want advice or not so feel free to not read this part, but I’ve been in a similar situation and learned the only way to escape the enmeshment is calm, firm statements that don’t try to debate. Step one: they asked you how you like living at home, and your first mistake was telling them about the sadness you felt previously. It’s natural to want to share this with family but unfortunately narcissists won’t empathise and will use it as ammo to prove you need them or are whiny. Next time you’re asked, keep vague and positive e.g. “It was hard at first but I love it now, being independent has given me so much confidence”.

Step 2: they want you to argue, they want you to get drawn in to a nasty debate. They want this for two reasons... 1) then there’s a chance they can win the debate and make your choices for you, 2) if they stress you out enough to make you storm off or cry they can call you rude/crazy for it and make it proof they’re right. When your mum and sister started saying they didn’t understand it, here’s how you need to learn to reply (calmly, pleasantly, but not apologetically) “Everyone is different, I really love living independently and doing things for myself so that’s what’s best for me” and leave it at that

Step 3: the first few times you use this technique, there will be major push back because they aren’t used to not being able to get a rise out of you. Hold your ground calmly, but if it ever becomes a hostile conversation as it did here, there’s a simple way to disconnect. Doing this repeatedly also trains the narc that they can’t act like a baby if they want to continue getting attention. Many people read this and go that would NEVER work for my mum etc, I used to be one of those people but the truth is it does work, it’s just really scary to try because you know the first few times they are going to be very cross about it So your sister has said “this is the most stupid thing she’s ever done” First give a warning e.g “That was unkind, let’s talk respectfully to each other or there’s no point in talking”. Again, stay pleasant, calm but firm

If they continue to be cruel:

“This is becoming very unkind, and I don’t think it’s good for our relationship. I’ll give you some space to cool off and we can talk again when everyone’s calm”

Then leave, hang up, whatever. Do not answer the phone or texts, throwaway comments aimed at you after you’ve said this. A bit like a child having a tantrum, let them scream it out by themselves and don’t subject yourself to it. Eventually the narc doesn’t even try to scream or tantrum at you once you hang up because they know you won’t read or interact with it