When should i test progesterone level

I have normal 29/30 day cycle. I ovulate on CD16. But my doctor is requesting to do progesterone test after ovulation on CD21. Which only makes it 5 days after ovulation. Should i ask to get it checked on CD22 instead? Im just worried that my progesterone wont peak on CD21. As i read progesterone peaks 6-8 days after O.

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