I used to work at Jo Anns. It looks like 1980's colors and fabric could be a poly cotton mix. That would account for smaller size. wash in a lingere bag and do a fabric content test: burn a small piece over a safe surface (glass) - if it melts to a hard ball...or any hard pieces on it - it has synthetic fibers. If it burns to an ash, no hard pieces and smells like burned hair-it is cotton. I dye fabric and use this test to pick dyes for "mystery fabrics".
Good luck.