I'd say that problem comes in two parts.
One is... maybe the right way to describe it is hormones and experience?
Like, the first time you fall in love as a teenager, it's intense.
You literally have never felt that way about another person, ever. And, sure, from a cognitive development perspective, you're an adult, you just don't yet have the experience to deal with it.
That's true for a lot of life, and well beyond being a teenager.
As a teenager, you are, cognitively, a newly-minted adult. You don't know where you fit in the world, much less where you are going, and you're at the beginning stages of sorting out who you want to be. And sure, adults can give you advice, but only you can go through the process of figuring out who you are.
You are also, at the same time, both absolutely confident and totally insecure.
It's rough, full stop. My teenage years were hell on my parents.
This is compounded by American culture and education thoroughly insulating kids -- well into young adulthood! -- from developing emotional maturity or learning to accept responsibility.
That's all about upbringing, by the way. I have met teenagers that I would rank as more mature than a large number of people in their early thirties.
It's totally possible, and from what I have seen, easier -- we just don't do it.
Americans also do nothing, or at least nothing effective, to equip kids with critical life-skills: financial management, personal fitness, nutrition, martial arts, negotiation, the list goes on. The only thing we prepare them for is to "go to college".
That has to change.