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.
Continuity mistake: When Spyder is arrested he is more or less naked because the cops wouldn't let him dress. Then in jail you see him and Cook talking and he's got nothing but a blanket on. However when the show a clip of him during his arrest on 'Bust TV', he has a t-shirt on.
Other mistake: When Ross drops Cook and Nikki off after he and Cook have spent the afternoon running errands and buying ingredients, Cook gets out of the car and goes straight into the motel room, without taking his ingredients with him.
Continuity mistake: Cook wears his white cowboy boots with pant legs tucked inside them throughout movie. In the scene where Ross returns to motel , Cook questioned Ross if he had touched her? Cook draws his pistol and presses the barrel to Ross' face. Cook is wearing white/black sneaker ,clearly visible at 0:27:33 . The same scene at 0:28:48 Cook is now wearing white cowboy boots with pants legs tucked inside . (00:27:35 - 00:28:35)
Answer: They never mention age, as far as I can see, and I just watched it recently.