For the last 8 months or so, I've been dealing with a tricky situation. My best friend is getting married, and I'm in the wedding, but I had to try and buy the bridesmaid's dress in October for the wedding in August. Since I was in the middle of my weight loss journey (and still am), this took a bunch of guesswork.
When I first tried on the dress back in September, I fit into the size 20. When I bought it at the end of October, I fit into the size 18 but bought the size 16. Luckily, David's Bridal lets you exchange the same dress for a different size. Today I just got back from exchanging it for a size 12!

It doesn't quite zip yet, but I anticipate losing another 25 lbs before the wedding, so it should fit by then.
Thank goodness the bride has been really understanding about the whole thing. She's had wls, so she knows all about going through sizes rapidly. Not only is she really understanding, but she is also very encouraging about taking a chance on the smaller size, saying she knows I'll be able to fit into it by then. Overall, it's very exciting, especially considering this was causing me some concern over the past several months.