Progesterone test

MM • 30. Married. Pug mom. 👼🏻 7/14/20. 👶🏻 8/5/21 🌈

So my last cycle was 36 days long

I’m pretty sure I ovulated cycle day 16-17

I’m now on cycle day 21, and doc wants to test my progesterone levels to confirm I did ovulate. Is she testing at an accurate time though?