As a society, through laws, we've decided there's an age where a person is mature enough to be granted autonomy separate from their parents. If we start trying

As a society, through laws, we've decided there's an age where a person is mature enough to be granted autonomy separate from their parents. If we start trying to decide when they're mature by brain development we'll probably find the brain never really stops growing and changing and even if there is a general age it'll be different for every person as everyone develops differently. That's an untenable standard.