1950s vintage sleeveless button down floral Peter Pan collar shirt

Red floral button down vintage shirt, most likely from the 1950s. No rips, tears or holes. Discoloration around the collar and one blemish/ discolored spot on upper left top (see photo). Good used condition. Length- 22 inches Arm pit to arm pit- 19.75 inches My guess is roughly a modern size medium. Compare these measurements to something that fits well that you already own to know if it will fit.