I remember those sweaters---late 60's early 70's I believe. Worn at the length yours is with jeans or a mini-skirt. Same "sweater" a little longer worn as a dress over brightly colored tights with "go go" boots (white ankle highs)
i have a shirt sort of like that-only it was red and the sleeves weren't connected, but it looked like they were. it was mom's, she said it was called a butterfly shirt.