I returned the wedding dress without telling my mother

Dear Delyara, The sales assistant recognized me when I carried the dress back into the shop. She smiled and asked whether the wedding date had changed. I said yes because it was easier than saying the wedding no longer existed. My fiancé left eleven days ago after admitting he had been seeing someone from work. My mother still thinks we are “taking space,” and the dress was hanging in her guest room because she said keeping it at my apartment before the ceremony was bad luck. Today, while she was at a doctor’s appointment, I took it from the wardrobe, folded it across the back seat, and drove to the store. The assistant inspected the lace, checked the receipt, and refunded the money to the same card my mother had used. She said, “I hope the new date is beautiful.” I thanked her. On the way home, my mother called to ask whether I wanted her to make soup. I said yes and drove the rest of the way with an empty garment bag on the passenger seat. She will see the refund eventually. I do not know how to tell her that she lost the wedding before she had the chance to wear the dress she bought for it.