I am between size medium and large in adult t-shirts and tops. I tend to wear a 10-12 in dresses and swim suit tops. I wear a 38D bra. I bought the Large and am thinking maybe I need an XL... The arms are fitted but loose, the arm pits fit and are comfortable, but the neckline feels weighted down due to my chest pulling on the chest seam. Also, stitching where cords are isn't convincing me it'll hold up over time. It is very feminine and cute. I cant wait to wear it kayaking.