Fun fact: the "brain is fully developed at 25" thing that everyone refers to is just completely wrong. The study that is being is referenced when it got brought up wasn't even looking for that. They were studying maturity in people from kindergarten to age 25 and found that people mature at vastly different rates: with some children being more developed than some adults. The 25 number was an arbitrary stopping point because they didn't want to study people for their whole lives.

Now that being said, kids shouldn't smoke or drink. But not because of a misunderstood 20 year old study