Apparently it's 30 now (https://www.bbc.co.uk/news/newsbeat-47622059
). Given that brain function then starts to decline from ~45 (https://www.bmj.com/press-releases/2012/01/05/cognitive-decline-can-begin-early-age-45-warn-experts
) we have an extremely small window when we should be allowed to make our own decisions.
I would argue that the brain never stops developing. Although the development tends to be more than offset by degradation after a certain point.
I cannot help but feel that some of the scientific rationale here is poor. It's a little outside my best expertise, but the argument is that the brain undergoes a "rewiring" due to puberty that is complete ~25 (or as more recent papers suggest, 30). However, the brain does continue changing. If you work on a certain sort of activity, your brain can alter to increase the amount of activity in the required areas, and it can do this in your 40s, 50s. Bits used less may dwindle. What, exactly, is the justification for this completed "rewiring" separate from other development? I cannot help but wonder if it's kind of bullshit: interpretation overreach.
I also wonder what role experience-dependent learning may have on it. Maybe we take until average 25 to develop because our parents look after us so much, so we've yet to learn and form those connections that tell us "Stop taking sickies or you'll get fired".
What's also gibberish is an argument that "adulthood" means a sort of maximal growth, where things level off thereafter. But let's take muscle. At some point in your 40s after a life of idleness, you decide to become a bodybuilder. You will surely end up with larger muscles than you ever had before, so does that mean you became an adult at 44, because it was the point of maximal muscle development? Surely not. So why would we make that argument about a brain? There are arguments blah blah brain development impluse control blah, but then why can some 15 year olds be more "mature" (psychologically) than some 35-year-olds, despite having a less developed brain?
Problems, problems. I am very skeptical.