Vintage 60s 70s floral Sundress from Dash About

Vintage Floral 60s/70s Sundress listed as size 18 but that does not equal modern size 18! Please go off measurements. Features built in bra cups, adjustable button straps, side pockets, smocked elastic back, fit and flare type skirt. In great condition for vintage! Slight discoloration on left strap that probably can be solved with baking soda paste and sunshine. Pricing reflects the slight discoloration though. Length approx 42" Waist 13" unstretched,  stretches to approx 17.5" flat Pit to pit approx 17" flat AGAIN, VINTAGE SIZING IS NOT A MODERN SIZE 18. GO BY MEASUREMENTS. Happy to take more or answer any questions listing as a M to help any confusion