When did I fall pregnant 😩

[Tabithalevi]

Hi, I’m new to all this but I really do need some help 😔
I had a “period” on the 26th November which lasted 5 days ended on the 30th I then had intercourse around the 4th December and again on the 10th leading to the 11th December. When was I most likely to have gotten pregnant? I have an app which says I was ovulating around the 11th December but not sure how accurate that is because my periods can sometimes be irregular.

I also had my 1st scan on feb 19th 2021 they dating me 11 weeks 5 days but I would have been on my period then so it doesn’t make sense to me. My due date is 5th September 2021 and am now 15 weeks 3 days according to my first scan.
Which date was I likely to have conceived. Please help me smile 😔 x Hopefully this makes sense

Pregnancy is dated from your last period so your dating scan makes perfect sense. 11w5d means you would have conceived approx 9w5d before your scan.

... give or take a week. Assuming a dna test will be necessary? Is that why it matters?

You would have conceived approximately 13th Dec based on your scan measurements and matches with your approximate OV date

What difference does it make? You've had the dating scan?

I think 6 days difference it’s impossible for anyone to be 100% even though it’s more likely the 10th, you’ll never really know. Is it important OP? As in a difference of fathers?