You have quite awhile, you need to wait until the plant has alternating nodes (branches growing in the famous mj pattern) at which time you switch your lights from veg (24/0 or 18/6) down to a 12/12
Also, what kind of light do you have? You should get it closer to the plant so the plant doesn't have to grow so tall just to get to the light.
if nothing else, put the plant closer to the light (2-4 inches away). i keep mine at about 2 inches and my plants are growing about an inch every 2 days.
it looks like it has had a little stretch to try and reach the light source.that could be the reason for the long thin stem, yep bring the light closer