AITA for not wanting my siblings gf at my college graduation when I don't have a relationship or know her very well at all. My brother and I are really close, and so we have a very strong bond and have inside jokes with each other, and bully each other, and use sarcasm to communicate, and she's an only child. She's also introverted and overall a quiet person. My sibling (26) and his gf 28) have been together for 2 years. I've talked to her a total of like 3 or 4 times, and all were very brief or little conversations. They moved in together after only dating for 3 months, and he introduced her during a big family trip. I didn't find out about her before the trip, only my mom was the one who had met her. I learned about her through my mom when she found out about it; that's how I also learned I shared a birthday with her.
The first time I met her was when she was at our house, and it was less than 9 months into them dating. I wasn't feeling well, and so I didn't have the best first impression. The only contact I have with her is with is via Instagram, and we rarely interact as it is. I have serious RBF. Turns out she said to my brother that I'm a mean girl in disguise and that I don't want her dating my brother cause she is a skinny white girl. My brother told her none of those things were true, which helped reassure her. Fast forward a few months, going over plans for graduation, and knowing that I wanted family at my graduation since I was a sophomore in college before they even knew each other. There were many times my brother could have brought up wanting her to come and didn't, my mom assumed she was coming along since she was with my brother, and that she was always welcome, and instead of talking to me about it and finding a solution he went off on text with our mom being like how could she feel welcomed when she wasn't invited or none of y'all mentioned including her in the celebration.
My mom told me all about this after the conversation they had and I was like I don't consider her family, I don't have a relationship with her and they live in a different state so the only time I ever see him is during holiday events, and usually she is always tagging along so it would be nice to just spend time with my brother like when we were younger, and other family members who I don't get to see very often and have a nice time just laughing and enjoying family company. It's nothing against her, I just don't feel like I have a strong enough relationship with her to invite her or feel comfortable with her being there, knowing that's all the family was going to be talking about is her instead of focusing on me and my accomplishments and struggles. My brother doesn't talk to me about his or her relationship or ever indicates wanting me to get to know her more or even form some kind of bond, and it's hard when she doesn't talk to me when we are in the same room, or the conversations are awkward when i try to start them without my brother being in the room.