Bridesmaid Postpartum

Ok first time mom here so this may be a silly question... I am going to be a bridesmaid in two weddings at 3 and 4 months post partum next summer. I know I'm still going to have a bit of an extra belly at that time, but I'm a huge planner and would love to be able to buy dresses in advance (both brides are giving out color chips and letting their bridesmaids pick styles they are comfortable in. thank the lord! ) Based on your experiences, about what stage in pregnancy do you have about the same size belly as a few months post partum? I'm currently 8 weeks exactly and really haven't started expanding too much yet. I know it is different with everyone, so just looking for personal experiences. :) TIA!