Teenagers are adults. That's just basic biology. No one reaches "full maturity" in their 20s. That's ridiculous unscientific garbage 😀
We have raised our teens to be totally unprepared for parenthood. Our culture created that. Other cultures historically did things differently and got different results.
We delay starting families now. That's fine. It's still very important to teach young people about sex, contraception, etc. Also important to provide contraception. We know how to prevent unplanned pregnancies. Let's do that.
Women under 22 are not girls. Calling them that is demeaning and degrading. Infantilizing our young adults caused tons of problems. We need to stop doing that immediately.
Young men and women are perfectly capable of choosing their own romantic partners. Some will get hurt. There will be some sad breakups. That is part of life.