Like the title says, my (F29) older sister (F33) is expecting to be my MOH.
To give some back story, my entire life my sister has hated me. She was adopted at age 2 and I was not, so there was always resentment towards me. Throughout our childhood, she treated me terribly, physically and mentally bullying me. Not sure if this is important, but she is a diagnosed narcissist, has borderline personality disorder, and is suspected of having histrionic personality disorder. We did not find this out until much later in life, so for years, it was just me getting the brunt of her lash-outs. This was also compounded by the fact that I was always good at sports, did well in school, and had a lot of friends- all things she did not have and resented me for. Because of this, she would purposefully try to ruin these things for me, whether it was making up fake drama to tell my friends I said about them, hiding my schoolbooks before an exam, or anything similar like that to set me up to fail.
Around 5 years ago, she got engaged to her boyfriend. She has never been able to keep long term female friendships, so because of that, I was her maid of honor. She did not have any bridesmaids because of no strong friendships, so I was forced to do everything. Also something to note is that we come from an immigrant household, where in our culture your sister is ALWAYS your MOH. Recently, I got engaged to my fiancé, and my mom, aunts, cousins, and entire family is pressuring me to make her my MOH. I have 15 girls who are my best friends in the world, that I want to be my bridesmaids, and I was either going to choose one of them or my younger brother (bestie) to be my MOH. I truly think that if she is involved in any way in my wedding, wedding planning, or even much of my adult life, she will try to sabotage it in some way or will make it all about her. I do not want to disappoint my parents or my family though, so WIBTAH if I chose one of my friends or my brother, despite knowing how much it will hurt her, my mom, my entire family, and go against our cultural norms?
I really do not know what to do, so any advice would be appreciated. Thank you!
edit: From what you all have read, you have probably realized that I do not have a good relationship with her, nor do I want to have one. I genuinely do not want her to be around my friends as she embarrases me and I want to spend all of my time with my chosen sisters. I would not want her to be around them at the bach trip/getting ready/ showers/ etc.