LOL, that's funny. Though, it occurs to me (which makes it even funnier), she wanted to know if you were going to wear it at a particular place (someone's party, etc) when she asked where you were going to wear it.
So, many years ago, when my sisters and I were all kids, we would go to my granny's and papa's house (my maternal grandparents) for supper. Their table wasn't big enough for everyone one to sit at, so my parents would sit at a table with Granny and Papa, along with my eldest sister, while the remaining three of us sat at another table they would set up nearby.
One time, we were all happily eating and my younger sister looked at me and asked, "Joy, whose auntie will we be?"
She asked the question fast, blending the words together so I heard, "Willwebe", as if it was some strange name. I thought she was asking about some obscure relative she had heard mentioned and wanted to know more about. I had no idea who this Willwebe person was. "I don't know. Who's she?"
Her: No, whose auntie will we be?
Me: I told you. I don't know.
This went on for a while, sounding like a bizarre version of "Whose On First". Even my mother was confused because she was hearing the same thing I was. The more often I said, "I don't know. Who?" or "Never heard of her." The more frustrated she got. Finally, just about in tears, she slammed the flat of her hand on the table and shouted, "No! Whose. Auntie. Will. We. Be."
"OH, that." I said. "I don't know, since none of us have had kids yet."