AITA for refusing to give back a family heirloom?

A few years ago, my mom gave me a beautiful gold bracelet that originally belonged to my grandma. It had been passed down to my mom, and my mom told me she wanted me to have it because I was the ‘responsible one’ (I’m the oldest of her children) and would appreciate it the most. I was honored and have worn it regularly since.

Now, my younger sister (22F) is getting married, and my mom decided she wants the bracelet back so she can give it to my sister as a wedding gift. I was shocked because, as far as I knew, it belonged to me now. My mom keeps insisting that it was never meant to be ‘permanently’ mine—just in my possession until it was time to pass it on. But she never said that before.

I refused to give it back, saying that if she wanted it to go to my sister, she shouldn’t have given it to me in the first place. My sister is now upset because she thinks I’m being selfish and hoarding the bracelet out of spite.

Most of our family also thinks I’m bitter towards my sister because she’s getting married, and I’m unmarried, but that’s not the case at all. I’m happy for her, I just want to keep the bracelet as it was given to me first.

AITA?