Quick CD Question!!!!!!

Er

I was given Clomid due to my Progesterone level results being low. I was told to take them from CD3-CD7 (50mg). I am excited but unsure to count today as CD1. My cycle literally just started and it's 9pm, is today considered CD1? I'd say yes but I want to make sure I take the clomid correctly as we are TTC and have been unsuccessful for almost 3 years now .