> The main challenge is that the prefrontal cortex, which is responsible for impulse control and other things, only fully develops around age 25.

This factoid has been repeated for decades but it’s essentially a myth.

Brain development continues into your 20s, but there isn’t a threshold at age 25 where someone goes from having poor impulse control to being capable of good impulse control.

18-25 year olds are not children and are fully capable of having impulse control. That can continue to develop as they age, but it doesn’t mean age 25 is when it happens.

I would agree that actual children need some more explicit boundaries, which is also why we don’t allow children to do a lot of things that people over 18 can do.

I don't think anyone is saying impulse control goes from 0% to 100% on everyone's 25th birthday, like flicking a switch. But is it not reasonable to say that a 25-year-old will have significantly better impulse control than they had when they were 18? (And that their 30-year-old self probably has a similar level of impulse control as when they were 25?)