Ruched sweetheart one-piece swimsuit in green gingham

I bought this, unfortunately on final sale, in size 0, which fits me perfectly in the ruched strapless suit. It definitely runs smaller. I would size up one if I could exchange.

This runs small, to me. I’m usually a 2 (5’ 7’, 124lbs 34B, slender/straight) and bought both a 2 and a 4. I kept the 4. The 2 was uncomfortably tight. It’s high-cut in the legs, so it’s not full coverage (which was fine with me). I love the pattern and the ruching.