J.Crew Emilie Sweater Lady Jacket/worn once

J.Crew Emilie sweater lady jacket, size s. Worn once and then cold washed with steamery detergent and laid flat to dry. Excellent condition. This is my sister’s sweater. She purchased it several months ago and then didn’t wear it until a couple of weeks ago and it no longer fits her. I don’t see any flaws. Measurements taken while sweater is laid flat: armpit to armpit is 18”. Length is 18.5”. I think the white in the stripes is more of an off white/cream color and not a bright white.