Sunday Soho Puff Sleeve Summer Skater Dress with Open Back NWT SMALL

My mother bought this on a trip to New York last year with my daughter, who didn't care for it. It is a Sunday Soho NWT and never worn summer skater dress with puff sleeves and an open back. Size Small. Stored in a smoke-free home. There are thin cups in the two and the waist, arm holes, shoulders and back strap are stretchy/elastic with give. (Forgive my non-technical terms--I know nothing about fashion!) The dress can be worn with sleeves or with the sleeves off the shoulder. Measurement from the waist band to the front hem is "18 approximately and this appears to be an asymmetrical hem, where the back is a little longer than the front. The dress has a built-in slip in the skirt portion. I'm afraid I don't know sizing very well so please refer to Sunday Soho's sizing chart.