positive vs peak opk - when is o?

Mandy • Endometriosis dx 2015. MC Sept 2016. 🌈 baby Grace 11/26/2017.
I don't temp so I can't say for sure I know, but I'm trying to figure out how many dpo I am! Haha
I had 2 days of positive opks where the line was as dark as the control.
Followed by 2 days of positive opks where the line was darker than the control. Would it be safe to assume o likely occurred after that 2nd dark opk?
So confused! Haha