I know many young women who are quite mature. They've been cooking and cleaning, taking care of younger siblings, and taking general care of a household since they were 10 years old. They are proficient at any number of domestic skills such as sewing, knitting, spinning, etc.
These young ladies have grown up watching their mothers and have been allowed to flourish in their femininity in the protection of the cloistered home. Unlike young men who mature by going out to make their way in the world, young women, if left to flourish in their feminine nature in a good Catholic home, will mature as much as is needed to make a fine wife and mother, even before the age of 18. They have all the experience in life they need to be married at a young age.
It's true that our culture today does not encourage this kind of upbringing, but good Catholics will always remain, no matter how small the number may be. Let's not let the times make us so cynical that we scorn what is good.