This is the Mint Maxi Dress by boutique children's clothing designer Well Dressed Wolf for size 2T. The dress is new, the tags have been removed, and it retailed for $120 originally, I think. It’s really a magnificent dress. Perfect for a little wedding guest.
Did they go out of business? WDW? I believe they may have.
The dress looks like it may run a little long, please check the measurements. It is 100% lightweight woven cotton, is fully lined, and there is a sash to tie around her back.

27 1/4 inches long

10 inches wide with elastic in the back that stretches to 10 1/2 inches