yeah that’s true. From the beginning of human history to about the 1980’s, all mom’s were “teen moms.” Now it’s a dirty word like it’s something to be ashamed of because you’re putting off your career. When you are young, that’s when you should have kids. Not when you’re in your 60’s.
Not always... there was a cultural habit among the poverty-stricken Irish to delay marriage so as to limit the number of mouths to feed. Also, things like family obligations due to their being no welfare and things like wars tended to interrupt many a courtship.
Back in the ’30s-’40s, one of my Irish-descended aunts “went steady” with her fiancé into their mid-thirties—but he was drafted and spent much of WW2 in Europe in an essential role, so much so that he was held over in France to do after-accounting of supplies. He finally got home months after the war ended, they finally got married, and had their first child at age 42. Another aunt on the other side of the family took care of her invalid, widowed mother until her mom's death when she was in her mid-thirties, and finally married and had her kids in her late thirties.
In both those stories of decent, lower-middle class American people who grew up in the Depression era, the men bided their time waiting for their sweethearts (we have a stack of very sweet love letters from their times apart), as both of them worked to save money for a house for their eventual marriage. The women got jobs as secretaries or clerks, and the men went into trades. An out-of-wedlock pregnancy would have resulted in losing a job and not getting a good reference (women) and wrecking their standing in their churches, neighborhoods and possibly their families (both).