Lmp = 7 weeks But Ovulation date= 4 weeks

So i was wondering if anyone has any experience with getting pregnant on late ovulation. My LMP was Nov. 16. But I did not ovulate until 12/20. when i called today they are thinking of me as 7 weeks pregnant, but i know i am only 4.

Anyone have experience with this? It’s not possible that i am 7 weeks right?