AITA for refusing to let my sister alter our grandmother’s wedding dress?

I (28F) have a sister, Dana (31F). We’re close most of the time, but she can be intense when she wants something.

Our grandmother Rosalind passed away this spring. She raised us half the time while our parents worked, so it hit both of us hard. When her will was read, there were no surprises except one. She left me her wedding dress, a 1958 ivory lace gown she wore for 51 years of marriage. She also left a handwritten note tucked in the garment bag:

“For the granddaughter who still believes in the long way around. Wear it exactly as it is. It has never needed fixing.”

I’m not engaged. I’m not even dating anyone right now. But I cried for an hour and promised her I’d keep it safe.

Two months later, Dana got engaged. A week after that, she asked if she could “borrow” the dress. I said of course, and I meant it. I’d be thrilled to see her walk down the aisle in it.

Then she told me the plan. She wanted to cut off the long sleeves, shorten the skirt to tea length, remove the lace hem, and dye the whole thing blush pink “to match her aesthetic.” She’d already booked a seamstress.

I said no. I told her she could wear it exactly as Grandma left it, and I’d even pay for a professional cleaning and fitting. But no cutting, no dye, no alterations. Grandma’s note was very clear, and the lace hem can’t be replaced once it’s gone.

Dana lost it. She said I was being “precious about a piece of fabric.” She said I’d never even wear it, so I was hoarding it. She said Grandma would have wanted her to have it, because she’s the one actually getting married.

I stayed calm and said, “Then wear it as it is, or don’t wear it.” She hung up on me.

Since then, my mom has called twice asking me to “just let her do it, it’s one dress.” My aunt texted that I was “making a funeral out of a wedding.” Dana posted a vague story about “people who value objects over family,” and half our relatives have been commenting hearts on it.

My best friend thinks I’m right but says I could have softened it. My cousin thinks I’m being rigid since “it’s just a dress.”

I keep going back and forth. The dress is legally mine, but Dana is my sister, and I hate that this might cost us our relationship.

So, AITA for refusing to let my sister alter our grandmother’s wedding dress?