Found some pics of cover pages in magazines of old fiction that seem to suggest it's a right of passage for underage boys to have sex. In one the girl is underage too. Both are "magazine art" that seem to be the first page of a fiction story. I googled the listed authors, and they are real authors, so I think these are real stories, not just a drawing on a page.

In this one the girl is underage too, but looks older than the boy. "There is one bitter conflict every boy must face" lol

1953 The Awakening, Earl Mayan Art, 1950s Magazine Art, Vintage Wall Decor, Mid Century Americana

In this one he's 17 and much older woman. "You've got to grow up sometime" LMAO

1950's Vintage Magazine Illustration, Story Art, 1950's Couple, Magazine Story, Great for Framing or Collage.