Factual error: The whole movie shows methamphetamine constricting their pupils. Methamphetamine is a central nervous system stimulant which dilates the pupils - the exact opposite of what is shown.
Factual error: In some of the shots where the cook is making meth, he is smoking cigarettes. The chemicals involved in making meth are so flammable that if somebody even walked past the room smoking, it would have exploded.
Answer: They never mention age, as far as I can see, and I just watched it recently.