Dude that told you it’s cause lack of nutes is wrong. You only have one single blade set of leaves. Coteledons shouldnt start to yellow for first week and a half atleast unless you’re watering wrong. It’s your watering is the issue. The roots are probably not developing well at all compared to what they should right now too. The amount of light you have is too much right now. A couple 23 waters 3-4” from each plant is perfect right now