Trichomes Hemp and High CBD Strains

So…I’m growing high CBD plants, essentially hemp. How can I identify the peak production of CBD. Does the “amber” rule still apply?

I have plants that are 12 weeks from germination and no signs of amber.

Really perplexed as to when to harvest !

Everything I read on CBD plants says when they are milky white harvest then. Dont wait till you see amber. Once they start to amber the CBD levels start to drop.