Who of us is mature enough for offspring before the offspring themselves arrive? The value of marriage is not that adults produce children but that children produce adults.
Marriage is a core institution of societies throughout the world and throughout history. It's something that has provided permanence and stability for our very social structure.
When I think of a merry, happy, free young girl - and look at the ailing, aching state a young wife generally is doomed to - which you can't deny is the penalty of marriage.
It's very different than it use to be. I think everybody has a lot more experience in how to be in a relationship - whether it's a marriage or a significant other or a business or a friend.