Yes, you can flower anytime you want to. All you have to do is look at your height restrictions. If you have only 4ft of height space, you'd want to flower when the plant is about 1.5-2ft tall. Remeber, at the end of veg time, the plants size at that time will double, some even triple in size by the time they aredone flowering. Of course, the bigger the plant, the bigger the buds, thge smaller the plant, the smaller the buds. Good luck.