I am 5'4" and 126 lbs and the small seemed to swallow me. The fabric is comfortable and the print is cute. The one thing I didn't like was that the top of the dress where the buttons are if the fabric flips over its black instead of patterned. I returned and didn't order smaller size.
I am 5'3" 126 lbs and usually wear XS-S in sweaters. Went with the XS on this one and was glad I did. The sleeves are more bell sleeved than appeared in photo. The material is a dream - can't wait to wear when it gets colder.