Vintage handmade 1970’s dress

I adore this dress, but the chest is too tight on me. The material is not stretchy, so definitely needs to be worn by someone who does not have an ample chest. The mannequin I use is a size small to medium, so that is why the dress did not zip up on it. This dress measures 14 inches from armpit to armpit. It measures 26 inches down from the armpit for its length. It was knee length when I used to wear it and I’m about 5’1”.