Are you marrying Mr Take That on Tour?
Fine. It's a cool look and you clearly have an idea about the feel of the wedding. Barn, tea length dress (anywhere from a few inches below the knee to mid-calf, from what I can tell, to the poster who asked what it is), relaxed atmosphere, etc. I'm on board.
But, DO realise it's best to complement each other on the day. Aesthetically, if for no other reason.
DO inform your guests, as has been mentioned repeatedly.
Do NOT be snippy with posters who ask about your choices, even if you infer disapproval, because you did ask this question on a public forum (on AIBU OF ALL THINGS) with a million opinions available.
DO match the dress (general, not your actual dress) to the venue and style of wedding. If this were a church wedding, I'd ask a few questions about what type of church you go to. God won't mind, but traditions are there for a reason, and I think the idea of "all this new formality trend" (not said by OP) shows that many today don't have a clue about respecting the traditions and cultures that have meaning to so many people.
DO have a wonderful time and accept my best wishes. 