It's fairly casual. Does that fit the "vibe" of the wedding?
And it could photograph very white.
My personal opinion: The dress would be too casual for most weddings. And if it isn't too casual (due to the event being rather relaxed), I'd worry about the bride wearing a rather "relaxed/boho dress" as well (and this photographing as white).
So no, I would not wear this (unless you're close enough to simply ask the bride in advance or know what she's wearing...).