AITAH for complaining to my gf for how she acts towards my little sister?
saturday evening I (M20) met up with my family and my gf (F20) came along too, at my mom’s place. My gf and my little sister (F13) have never really interacted much which makes sense, my sister’s shy and they don’t have anything in common. however this time my gf acted in a way that came off as just antisocial.
first thing, my sister made a cheesecake by herself and when she laid on the table she wanted to cut it, my gf already had the knife in her hand and was about to cut it, she mumbled and sighed when my sister said she wanted to cut it and continued to cut it. I thought okay whatever, later as we were sitting round the table my gf makes no effort at all to talk to her and sometimes interrupts her. at one point my sister reached across the table to get a plate of something and she drops the plate on the table which knocked stuff on the table over. my gf said “what the hell..” quietly as she moved her plate away from the stuff that was knocked over, she seemed in a mood over that for no reason.
I noticed all this and I spoke to her when we got back to the house and I said she could at least cheer up a bit when she’s interacting with my sister, she’s only 13 so just talk to her a bit. She says she doesn’t think how she acted meant anything and she has nothing against her, just minding her own business. I told her I just think it doesn’t take much effort to be friendly to ur bfs kid sister and how she acted was kinda bitchy, she said I care too much because she didn’t do anything explicitly wrong and im just nitpicking, noone cares that much about interacting with their partners little siblings. but i’m not expecting her to form like a close bond or anything but just don’t air her completely when we’re sitting round the table with family. am i being too naggy over this or is it valid