AITA for telling my brother’s fiancée she can’t use my wedding dress?

I got married three years ago and had my dress professionally preserved. My brother’s wedding is coming up, and his fiancée asked if she could wear my dress to save money. I said no because it’s sentimental and I plan to pass it down someday. She got quiet and said, I thought you were family oriented. Later my brother texted saying I made her cry and that I should reconsider because it’s just sitting in a box. I told him it’s my dress and my decision. Now my mom is telling me I’m being selfish and causing unnecessary drama.

AITJ for saying no?