I want people to respect each other. and unwarranted infantilization is very damaging. Our teens are having a massive mental health crisis right now. They are depressed as hell and killing themselves at rates never before seen. The way we treat them like shit, tell them they're idiots and will be for 10 more years contributes to this.
We've not changed the way we see adolescent development for far longer than mental health and suicide have been rising, meaning your ideas of what's contributing aren't even remotely the cause. You wanna know why teenagers are killing themselves in record numbers? Here's a few quick reasons...
Social media. Influencers have created an entire fake reality that is so impossible for the average person to achieve that they feel disconnected and worthless. The fact that these people make boatloads of money while producing and providing zero value to the economy is also disheartening.
Climate change. It's clear that it's happening, and clear that governments and their corporate overlords are willing to destroy the fucking planet while we can't do anything about it.
Cost of housing. Want to retire? Ever? Hahahahahahahaha hahahahahahahaha. Hope your family is wealthy or has a place to pass down to you.
Cost of education. In the last 50 years the cost of a bachelor's degree has risen 500% above inflation. Somehow this has also happened during a decreased value of education as well (so literally breaking the economics of supply and demand) because every fucking entry level paperclip counting job needs you to have a 60k degree to "prove you have the discipline to get things done."
But yeah, I'm sure it's the fact that 13 year olds aren't considered legal adults (something that's never been a thing in our society) that's somehow causing the increased suicide in the last two decades. Cause that makes any fucking sense at all.
Your straw man at the end is stupid bad-faith bullshit. The vast majority of teens are no longer 13.
There are other factors, of course, but getting treated like shit, being constantly told you're a moron, having your sex life criminalized, constantly being told you'll get groomed and preyed on because you're an idiot, getting zero respect, and having no legal rights is a major cause of the mental health crisis (which happened simultaneously with the change of paradigm from teens = young adults to teens = large children)