Dress too plain for MIL’s wedding?

So my MIL wants me to put my daughter on either burgundy or white.

The wedding is the weekend coming up. So I’m out of options. I had bought her a pink one but my sister said she’s going to get mad because that’s not the color she said. So I went to the mall and found her a white one, it’s not as nice as the pink one but I mean atleast she won’t get mad right? ... Now my family is saying it’s too plain. Me and my SO think it’s decent. I mean it’s not like she’s flower girl or playing a roll in the wedding. What do you ladies think? She’s going to get it dirty within the morning anyways.