Bottom leafs turn yellow

Lack of nutrients from growing in an inadequate tiny cup only half filled with soil. Transplant asap! It is almost impossible for a plant this size/age to show deficiency symptoms if growing in enough, decent soil.

To much water💚

I'm with Ninja.

Hi, brother. It looks like you've overdone something. We hope you're not using any nutrients for at least a couple of weeks. If you know the composition of the soil you're currently using, it should be sufficient, as many soils are already nutrient-rich. Check the ingredients in the soil from the supplier for soil-specific information and use only clear, pH-balanced tap water. Good luck, buddy.

Looks like it needs more sulfur

Super over watered

S deficiency, maybe? insufficient information provided, but the inside out paling points toward sulfur, and it looks to have progressed top-down on the plant. Leaf symptoms are indiscrete, so you need more information to cross-reference to confidently diagnose anything. the fact you are seeing major symptoms this early means your choices or products used for any fertilization are not working well in a profoundly bad way. if this is soilless, maybe you have neglected to fertilze each time? or if it is soil, it's a shitty mix for seedlings etc...