Ovulation day?

Jessie

Hi guys! I found out I was pregnant on Saturday! Now my question is how can I tell when I ovulated?? I didn’t have regular cycles and don’t ovulate regularly, but Glow told me my ovulation day was 1/13. I had sex on 1/9 the next day 1/10 I took an OPK (it positive it means the next two days are best to have sex) mine came back negative. I again had sex on 1/13, so I was just wondering if you think I ovulated when Glow said I did?