Some alterations needed
"For some reason, VB included a review I did for a different “Mylie mock neck” which featured a much stretchier fabric. This shirt has a heavier only slightly stretchy fabric which drapes differently and the fit on a medium makes the oversized armhole a problem. I still recommend sizing up to a medium if you are usually a small with a 35-37 bust, but you will probably want to sew a small dart on the non-ruched side and an even smaller one on the ruched side to avoid a gappy look under the arms."