Vintage 1960s labeled size 13 cocktail dress pink with scallop & bow back detail

Dark pink vintage 1960s cocktail dress with scalloped and bow back detail. The size label as pictured says 13 but waist measures 28. Tt looks like a modern size 6 to 8 to me. I am pricing it low because I actually don't know the modern size equivalent. I bought it on eBay a few years ago and it's in perfect condition there are no spots or stains or rips at all. Its beautiful.