I'm just having a guess, but I'd say that your girl friends may already know a few people who've had babies younger? If they've already seen it close up, they may've seen what it involves. Some people are ready for all that, others aren't.

Men can be pretty blind to what having a baby really is like. Sure they can stay home & do all the cooking & cleaning etc, but they don't have to carry the baby for 9 months first. It sounds shallow, but they on't have to risk 'ruining' their bodies with stretch marks/birth etc etc.

Its not that horrible, & its not all roses. Some women do choose to wait simply for selfish reasons like their bodies, or their party nights. It can be that simple.

If I'd been better prepared, I'd have waited at least a little bit longer. I was 17/18. I'd have had a few nights out & been selfish for a bit longer.

Like I said, everyone is different. These things matter to some, but not to others