how young of a plant can u extract THC for oil or canna butter?

So I have a perpetual where my flower room always has plants in varios stages. Due to nice weather I have niegbours out all day and fam planning on coming by to help me with work. Due to these factors I may pull the plug at any time. So if I shut down, how old do my plants have to be to contain THC to extract? Do my moms contain THC too?

any1??????????

how long have you had the plants in flowering??
well there will be THC in the leaves but not that much ( in the mothers )