Equipment Striped Oxford Shirt with Leopard Pocket M

Hi, this is a new without tags equipment striped top with a leopard pocket. It’s 100% cotton and seems like it should be comfortable. I’ve tried it in before, and it fits me until I move. I can’t figure out what exactly makes it feel small, but going by the bust measurement it should fit me. Maybe better for a small or a smaller bust medium. The pit to pit measurement is 19 inches.