I was reading this out loud to my little sister. She's also 10 and a jr. bridesmaid. She automatically shouted "no.!" She's so funny. My sister loves wearing dresses. You can talk to her and tell her it'll be just for a few hours. Try to tell her how it'll be nice for everyone to look the same. Girls her age don't really want to look different from other girls. If that does't work, well pantsuit could work. But just wanted to comment what my sister said lol.