you have to be short, with extremely tony skinny arms/ shoulders. Im  56 120, and the small was up around the top of me, arm holes smaller than Ive ever seen. Medium was the same on top, with too large/too much fabric happening on the bottom. Soooo disappointed.  I wanted 10-20 when I saw the designs, he slippery fabric and the simple pattern.

CowCow, if you ever make a dress just as this for my shape height, and some normal size arm holes, let me know, Ill go wild on those dresses!