Swing sundress or long tank

Top crochet area is not stretchy the rest is very stretchy. It fits like a medium thru the top than a large. Arm pit to arm pit is 17 1/4". So I listed it as medium even though the tag reads large. Wrinkles will hang out. Never worn. Online boutique purchase so no hang tags. It will be a short sundress mid thigh at 5'4". Shoulder to hemline is 31".