13 year old refuses the shirt his aunt bought for the wedding. Do we make him wear it?

Family wedding next Sunday. His aunt bought him a shirt for it. It's shiny. He says no. My partner says wear it for two hours, it's one day, she will notice and be hurt. I say he's 13 and old enough to choose his own shirt. He has offered to wear the plain kurta he already owns, which is perfectly fine. Who's right here? Not looking for 'pick your battles'. I'd like to know what you'd actually do.