If i let the plant grow for a couple weeks can i decide to flower whenever i want and if its only about 12 inches tall can i just go ahead and start flowering and if so how much would a plant of this height yield?
you can flower as soon as you want but the yield will definitely be less if you dont let it fully mature but without knowing anything about the plant other than height is impossible so what strain is it and do you have any pictures
in a way yes, in another way no. you can put a plant under 12/12 lighting if you'd like whenever but a plant cannot start flowering till it is large enough and becomes sexually mature.(preflowers and alternating nodes are a sign of that. they will show regardless of light cycle. however the female flowers do not always form right and it is highly advised you confirm a plants sex before killing it by putting into 12/12).