Fat grafting for lower eyelid circles
The best treatment for under eye dark circles depends on the cause. In some people the skin has darker pigmentation in the area which is quite hard to treat.
In other the dark coloration is from shadowing from facial volume loss. At your young age I would be reluctant to place fat in the area, though. Skin fillers such as restylane can be done at your age. Make sure you find an experienced surgeon to treat this area.