PCOS Ladies- When do you typically O?

Samantha • Mom of a beautiful 2 year old, Emmy. Trying to conceive miracle #2, TTC for a year so far with PCOS.
First round of Femara (Clomid failed me) at ultrasound today on cd12 I had a 12mm follicle... last 2 months got positive opk on day 18... when do you.O?