Forever 21 blazer, marked M but fits like S

Forever 21 nicely tailored blazer with narrow notched lapels, double welt pockets, two piece sleeves, and side panels. Fully lined. Thin shoulder pads. There are no button holes or buttons. It’s meant to be worn open. Marked M but fits like S. The mannequin’s measurements are 34/26/36, with a B cup. The fiber/care tag was removed. The fabric responded quickly when I steamed the jacket. Very good gently used condition. From a smoke free and pet free home.