Im usually a size small-medium in pajamas and went with a small since I saw photos of those my size or slightly larger in a small. Im 52 and 150 lbs and am a size 6, 34-26.

I have a tiny waist/flat stomach, but also a booty with thighs and more muscular arms. The top is a bit short even on me but because Im 52  and have a normal torso its perfect. I can just see how it would be really short/almost a midriff on people taller or with longer torso. The shorts are really short(total booty shorts), and Im just 52 but they fit comfortably! I did 4 stars vs 5 because the shorts are SO short.