Being a new grower (as I am too) affords you one thing especially, and that's the opportunity to learn a lot, I know I have. If your stems grow too tall because of stretching, you can use a temporary fix of cutting a straw to the right height, then slitting it down the side. Carefully spread the straw open and put it around the stem. this will work for a few weeks until 2 things happen, the stem starts to strengthen, and its time to transplant. When you transplant, just bury them a little deeper, only leaving an inch or two between the soil and the lowest set of leaves, as mentioned above. Taken from my experience, and your pics, you're getting a lot of stretch because the light is too high and too far to the side. You definitely need to figure out a way to get that light above the plants and only a couple inches away from the plants, or this will continue to be a problem for you. The longer them stems stretch, the less weight the plant can bear, and in the long run, the plant will either be very tall with fewer nodes, which equals less yield, or it won't be able to carry the weight of the buds. If your plants do get too much taller, you can always try doing LST, which will help counter both a height issue, and promote side growth countering the long internodal space, which in turn promotes more bud sites.
Good Luck and Happy Smoking.