This Skort/Jumper was part of my mom's 1960s clothing, which was stored in an attic (no mothballs) in the upper Midwest for many years. She was likely between a 2 and a 6 in current sizing, though she tells me she was a 12 (of course, that's in 1960s sizing, not in 2021 sizing).
I have not washed this dress and there is a slight "used clothing" scent about it but not strong. I did steam it for the photos and didn't think that the scent intensified. Looking at the dress there is a very slight yellowing on some of the white dots near the neckline. Armpit area shows no stains or damage. 
Item was likely purchased in Grand Rapids, MI and the brand is Go Young. 
There is no sizing on the dress. See above or ask questions. Note that the waist measurement is at the natural waist. The shorts actually start at the drop waist. Drop waist measurement to hem is 13". Dress is not lined.
Feels like Cotton; no info on the dress to determine the truth of it. Has a slightly stiff feel. 
Short openings at the legs is something like 37" for each leg! Rise on the shorts is 5". 
Zipper works well. Inside of dress shows some fraying at the seams. No pockets 

Feel free to reach out an ask questions.