The girls at my house decided to be the Disney Princesses for halloween and as the red head, I was Ariel. I am a fit track athlete, about size 3-5 and I ordered the small. The skirt fit me great, but there was no way I was going to fit in the top. Luckily I read the other reviews and bought a purple sports bra. Unless you are a size 5 with DD up top, be sure to only buy this costume for the skirt.