Vintage Handmade Square Dancing Swing Dress Polka Dot Floral White English Sz 12

It is white on top with a polka dot and floral bottom, there are floral appliques on the top as well
It has a belt (unattached) with it
The dress is vintage
Size 12 is a guess, see measurements below for a proper fit
Measurements (laying flat):
Bust: 18" (armpit to armpit- x 2= 36" bust)
Waist: 15" ( x 2=30" waist)
Back- shoulder to bottom: 41"

Appears to be cotton