Elephant Range mentioned that Bob sought to make his songs more versatile than specific. I think looking at it from a non-historical perspective, this song is about the author taking the virginity of a young girl without realizing it. It sounds like she was way more invested in the relationship than he, because she was young, inexperienced, and naive. He thought they would have just a fling and she thought they would last forever. I think she kept her virginity a secret: "But you said you knew an' I took your word" until after the deed, when she "told [him] later and [he] apologized." I think the refrain implies that the girl had to learn some time "You just did what you're supposed to do," and it might as well have been with him, as he actually did care about her when they had sex.
Elephant Range mentioned that Bob sought to make his songs more versatile than specific. I think looking at it from a non-historical perspective, this song is about the author taking the virginity of a young girl without realizing it. It sounds like she was way more invested in the relationship than he, because she was young, inexperienced, and naive. He thought they would have just a fling and she thought they would last forever. I think she kept her virginity a secret: "But you said you knew an' I took your word" until after the deed, when she "told [him] later and [he] apologized." I think the refrain implies that the girl had to learn some time "You just did what you're supposed to do," and it might as well have been with him, as he actually did care about her when they had sex.