In Canada we keep it simple. You have to reach 18 years of age and then all your behaviour is adult behaviour from that point forward. There's nothing else to it.
I don't think this is meant as a test to determine whether someone is an adult. I think this is meant as a guide to how to conduct yourself once you realize that you are an adult.
That's not true about age of consent nor is it universally true in Canada for legal drinking or smoking age or being tried as an adult. You can vote, marry and join the military at 18 however.
