What cd is the earliest you have took provera?

Hi everyone,

I have PCOS and this month on letrozole (2.5mg). I went in for a ultrasound (follicle scan) on cd 14 to check my follicle/egg sizes and to see if I am reacting to the letrozole and I’m not. On cd 14, the biggest follicle was a size 8mm. My OBGYN said I’m not reacting and canceled everything planned for this cycle, she just wants to wait for the next cycle to start. She told me to start taking the next set of provera on cd 34 but, I don’t want to wait until then to start my next cycle since I know I won’t ovulate. What is the soonest someone has started taking the provera during a cycle?