Your decision on when to trigger flowering should be based on the height of the plants. They will double in vertical growth over the course of flowering. If you want small plants, trigger flowering when they are small about 3 weeks old. The point of watching the height of the vegging plants before you flower is important because if you don't have enough light to flower a large plant, then the bottom branches will never get enough light and wont fully develop. When this happens those branches are taking valuable nutrients and water away from the developing colas-resulting in small nuggets. I would flower them right now or, in a week, if I was you because this is your first grow, and you should get a nice harvest from those plants in the pics .