biscotti okay?

That looks like a deficiency or ph issue. The yellowing didn't start from the bottom of the plant going up, so I am tempted to rule out Nitrogen. Calcium or Magnesium issues between the leaves veins usually look a bit different, but I wouldn't rule that out just yet. If you're feeding her Bloom already, she's possibly having to process an absurd amount of P and K which, usually doesn't get fed until the plant is actually in bloom. Of course, growing in Coco changes things a bit.. Without a diary though, I can't tell what your feeding habits are nor how much of each specific ingredient is being used. Perhaps you're under/over-watering. Perhaps your ph is off. Hard to tell without proper infos.