I bought this costume for my very tall 10-year-old. The description suggests that this size fits girls age 8-10. I am very tall, and this costume was even too large for me. Needless to say, it is way too long for my daughter, the bottom of the dress is basically on the floor.

It's a nice costume, not too expensive, and the quality is not too bad, considering the price. But I would recommend researching the measurements online before deciding which size to choose. The recommendation in the listing is wrong - it probably does not fit most of the girls in this age group. In the end, I ordered the same costume from a different seller in Medium.