A.W.
My daughter always wears old dresses as tops! When they become too short to wear as a dress, she wears leggings or even just shorts/capris under them. She wears size 8/10 really but the other day she was wearing a size 5 dress as a tunic style tank top!
Just buy the short sleeved and they can wear a long sleeved shirt under them or a sweater over them???