The other night, my older sister hosted a small family dinner. My girlfriend couldn’t make it because of her work schedule, so I showed up alone. I had recently bought an outfit for my girlfriend—something I knew she'd love—and had it with me because I planned to give it to her later that night.

My twin sister (who’s always been a bit clingy) noticed the shopping bag, asked about it, and i told her it for my girlfriend, she asked "only her?" What about mine? " pulling the outfit out. I told her that its ment for my girlfriend while i went to open the door for my elder sister husband, Next thing I know, she’s has put it on and strutting around like it’s hers. I shouted at her to take it off because it was meant for my girlfriend, not for her to “test out.”

She acted offended and brushed it off like it was no big deal, but I was genuinely upset. It just felt like a weird boundary to cross. She got moody after I confronted her, and now some family members are saying I overreacted.

AITA for being mad that my sister wore the outfit I bought for my girlfriend?