My daughter needed a long black dress for her Halloween costume. She is almost 14 but she is short. We ordered the size 12/13. It just fit in the sleeves. The dress lays nice and is stretchy so that is a plus. It hit above the ankle but will be totally workable. My daughter is about 58" tall and 84 lbs is this helps anyone with their sizing. We are keeping it but if this were a dress she was going to wear often, I would probably size up.

a bit long but my 4yr old in a size 7 is a bit short so not the companys fault the material is nice it has washed nice and upheld it is stretchy and durable the material itself has a coolness to it