Annoyed with bridesmaids

Currently less than 4 months out from the big day and not one of my bridesmaids have ordered their dresses. We’re ordering from Azazie and a lot of people on here have said they’ve ordered close to the date and we’re okay but I’m getting nervous. One girl still hasn’t joined the showroom and a few keep asking about the info for the dress like where to get it. My FH’s cousins gf
, who also lives with us over a year during the engagement still thinks she can just walk into a store and buy the dress. I’ve given them constant reminders since May and I’m getting really frustrated that these “adults” can handle accomplishing one simple task. If they don’t have a dress I’m not about to be running around like a chicken with it’s head cut off trying to figure out a back up plan because they couldn’t handle one simple thing. I’ll be really disappointed but they would just have to come as guests. Anyone else experience this or have any advice??