Should i flower?!?

hello My plant has about 5 nodes. i am Using low sress training because my pc grow box is about 24 inches high by 15 inches wide.the plants canopy is at 3 inches tall im having a problem because im training it into a bush and wondering when to flower.should i go by the hight of the canopy or how many nodes it has?or something else.please help i want to get i good yieldhere re some pictures

flower it when it is half as tall as you want in the end. i.e. if you have 24 inches total, flower her at 12 inches. good luck