For the past few weeks my sister (23) has been putting down everything I say, making me (17) pissed after most of our interactions. This mostly happened at dinner where I would talk about something I believe I had a decent understanding of, or simply correcting another family member about something, and she would get pissy with me by making it seem like I was a dick for sharing my opinion. (I know this sounds weird I’m just not very good at explaining it) An example would be me correcting someone on a subject and her saying “As if you know what you’re talking about” 

Naturally I got pissed off after she did this because I felt bullied, but I bit my tongue since I didn’t want to start shit up with my sister who I live with still. But today I was really grumpy after working all day, and was not going to have it. While eating dinner she did something mildly annoying, but after waiting for so many days I exploded on her. I said “Why are you being such a bitch recently? Everything I do or say you fucking get mad about ,” or something like that I can’t remember word for word. She was shocked but retaliated by saying she would slap me to which I taunted her to do it. My dad said that I would punch back (although I probably wouldn’t), and that deterred her.

After all this she barely ate anything for dinner and left to go to the bathroom and cry for a few minutes before composing herself and coming back to the table.

I’m not sure what I should do, as all I did was stand up for myself even if I was mean about it. Am I the asshole?

TL;DR: my sister has been bullying me recently and I yelled at her, making her cry 