Which day should I consider as my ovulation day?

Nikki • Pregnant 💚
I use the ClearBlue digital ovulation tests and got a "peak" reading for Nov 10 and Nov 11 and then a "high" reading for Nov 12. People often refer to their DPO and so I'm just curious as to which day would I consider my O day to then count my DPO. Thanks in advance for any help.