Tried this on in the store in a small (i'm a size 6 in most retailer dresses) and it was enormous. i'm short (5'2") so i knew i'd need a petite size. ordered a petite small and the length is better - still a lot of fabric, but i think a petite xs would be too small if you are curvier up top (i'm a full 34d and the petite small is just slightly tight in the bust). definitely size down in this or you'll be swimming in it!