When buying pre-owned clothing, don’t count on the stated/label size to be accurate for you. Check the measurements stated in listings’ descriptions.
A good seller will answer questions if you are unsure about something; and will offer returns — TheCurrentFashion.com does.
• Pre-owned clothing can be smaller (shrunk) or larger (stretched) than before it was first worn.
• Different manufacturers = different sizings.
“There is no mandatory clothing size or labelling standard in the U.S.” ~ https://en.wikipedia.org/wiki/Clothing_sizes#Standards