I think if it were an overwatering issue, the plant would be doing the "cringing wilt" thing. You're in coco, right? If she were a little older, you could flush and then give her new nutes. But she's still very young, and according to the wisdom at large, she should have every nutrient she needs still available to her from the seed.
That doesn't change the fact that she's obviously not getting something she needs. I've got a plant growing now that acted similarly at about this stage and started putting out really yellow new leaves. The plant eventually turned green again, but it's stunted beyond belief.
When they are this young, it seems like it has to be in the genetics.