BFP - how to work out due date/how far along I am?

Lauren

I am still in shock so until docs confirm it I think I will feel like it isn’t real.

I ovulated late in my cycle and have long cycles anyway, do they still count your weeks from the first day of your last period?

How can I work out technically how far along i am?

First day of last period was 25th Nov and I ovulated on 22nd Dec!