I would begin your trail riding experience on a smaller scale.
I personally don't like big groups like this, so many people and there are always issues. Horses kicking, broken tack, people wanting to be first, horses too slow in front, too fast in back, horses spooked, won't walk on, people needing to stop for personal reasons or whatever reasons, this is just to name a few. Also I personally would be miserable if I sat in a saddle for 6 hours.
I would start out with a few good friends and go on an hour or so ride. That way if you are the one with issues, you have someone there to have your best interest in their mind, wait for you, help you, maybe even turn around with you. Work your way up to the kayos of the big long ride.