Why going yellow from inside to outside

I wouldn't really worry to much at this stage but if you are, it looks like the start of an iron deficency. slow down on the watering and it should fix itself, iron tends to go hand and hand when the medium is to wet. I slso notice slight yellowing when plants are growing really fast or to close to lights at a young age. So less watering let pots dry just slightly and maybe back off light abit if its too close and it will fix on its own. Cheers