Postpartum Bridesmaid- HALPPPPPPP

Ma

Baby is due September 26 (FTM so I’m sure it will arrive late 🙃) and I’m in my sisters wedding November 9th... which leaves MAYBE a month postpartum. I’m not sure what size to order my dress in!? (Do I go one size up? Two sizes? What I would wear now with my 16week belly?) Any suggestions, ideas or advice on how to go about the best guess on dress sizes!? **posted is the Bridesmaid dress for all of us