I ordered a size Large, and I do wear size medium and large in clothes (I'm from Canada). The one thing was the top, it was a bit confusing as to how to tie what where but I figured it out.
Snug fit around my stomach but, I personally can stand to lose a bit of weight too (haha!) which would help. Was able to sit and stand and bend with no issues.
Outfit is comfortable to wear and is actually very pretty.
Overall, very happy with my purchase and can't wait to cosplay JC at Anime North (or out in public when picking up my MDZS novels)