[FULL] AITA for Standing Up to My Sister's Wedding Shenanigans?

Crazy sister lost her mind when I refused to walk down the aisle with her creepy brother-in-law and attack me. So I ripped her hair out. My sister says I can't be in her wedding if I bring my boyfriend, male 26, of five years. I met my boyfriend in college seven years ago and we started dating five years ago. He's super close and loving with my family. He was there at my sister's births, baptisms, Christmas vacations. We are extremely committed to each other for the long run but don't want to get married until we are financially stable and both our careers are where we want them to be. My sister has been with her fiance for two years and engaged for six months. My sister is the type of girl who has dreamed of getting married since she was a little girl. It didn't matter who proposed, she just wanted to be married. I have never cared if I got married or not. As long as I have a good career and a happy relationship, I'm fine. In the beginning of her relationship, she tricked me into going on a double date with her fiance and his brother. She had said it was dinner with her and a friend and it was most definitely not. The brother kept making passes at me the whole time and I told him I had a boyfriend. The whole situation made me uncomfortable. At their engagement party, my boyfriend noticed that the brother wouldn't stop staring at me and we tried our best to avoid him. Every time I've seen this guy, he's been weird towards me. My sister wanted me, my twin fraternal, and two brothers in her wedding. The wedding is supposed to be next month in the beginning of May. My sister just told me that I'm going to be walking down the aisle with her fiance's brother. I told her that he makes me uncomfortable and I thought I'd be walking with my own brother. Apparently, this is something her fiance is insisting on and she wants to make him happy. Seems like a pretty weird thing to insist on and I know it's some scheme between the two brothers. My other siblings also thought it was weird and voiced their objections to our sister. She got upset and said this is her wedding and she'll do what she wants. I told my boyfriend this and he was upset for me. He's confident enough in himself that he knows this guy would never be competition but he knows how uncomfortable I am with this situation. The other day, we had family dinner at my mom's house. I took this as an opportunity to bring up the situation with my mother around. My sister got extremely upset and started crying, saying I was trying to ruin her marriage. I was so confused, as was everyone else, and tried to explain that he makes me and my boyfriend extremely uncomfortable. She then said that I can't bring my boyfriend to her wedding anymore and if I do, then I'm no longer a bridesmaid. She gave no reason as to why I can't bring him and my siblings were just as upset, considering they like my boyfriend a lot better than my sister's fiance. I thought I would give her a few days to calm down and rethink but she has not changed her mind. My boyfriend is an incredible guy and has been nothing but kind and generous to my sister. His feelings are hurt but he still wants me to go to the wedding. I think my sister is being unreasonable and I will be pretty pissed off at the wedding if my life partner is not there with me. I love my sister but I don't understand why she's forcing some silly request by her creepy brother-in-law. I don't know what to do. My family's no help either. I went to my parents house with my brothers and told them about everything their brother-in-law has done that makes me super uncomfortable and how my sister is disrespecting my relationship. My dad was pretty pissed off about the date stunt that she pulled and is on my side. My mom however says that I need to try and resolve this with her because if I'm not part of the wedding party, people will talk. I honestly couldn't give a poop about what my extended family has to say. My mom called the family meeting and told my sister and my twin to come to the house. My dad asked her why I was no longer walking with my brother to which she responded saying that it's just what her fiance wants and she just wants to make him happy. I pressed the issue asking why it's such a big deal for me to walk with him and that he's super weird and I wouldn't be surprised if he tried to assault me. That really pissed her off. She started crying and yelling saying a bunch of BS about how this is all she's ever wanted and we're trying to ruin her special date. I was tired of the arguing and just straight up said I'll go to the wedding as a guest then. I'm leaving before the reception. My twin and younger brother took my side and said they don't want to be in the wedding party if I'm not. This made my sister lose her effing mind. She was screaming, calling me a bunch of names and also calling my boyfriend names. I decided to leave and let my parents calm her down but before I could walk out she ran at me and yanked my hair. Still screaming she wouldn't let go so I yanked hers too and she let go. She has extensions and apparently I effed them up and ripped some hair out. She tried to grab me again so I punched her in the face. I didn't mean to hit her it was just my instant reaction to someone coming at me. So now she has a black eye, a cut on her cheek and is missing some hair. She's absolutely livid because her bachelorette party is next week. My mom is mad at me, my dad is not. My sister is now saying that she's going to press charges against me. She's also pissed off because my other siblings won't be in the wedding. She told my mom if I apologize to her and agree to be in the wedding she'll let me walk with my brother. I feel like that is bs and she will still make me walk with the brother-in-law last minute. At this point I feel like it's not worth the trouble and I just don't want to go at all. My mom and dad want me to do what she asked because they're paying for the wedding and want all their kids there. My twin and younger brother said they'll do whatever I want to do but I don't think I should be the reason they don't go. My boyfriend feels like he started all this drama when none of it is even his fault.