I think it would be best when you are mature enough to be responsible for what you do and take the correct safety measures to smoke for me it was just this year. I now that when I am high I do not want to do stupid shit, but for others aka my friends I do not think they will ever be mature enough, but they have grown up some. So whether that is when 14 or 45 then whatever, but I surely do not think little two year olds should be running around smoking a blunt or getting shotguns lol