Trouble calculating due date

I found out I am pregnant. But I’m having trouble trying to calculate a guestimate of how far along I actually am (I haven’t seen my ob yet) my cycles are always irregular, they range anywhere from 22-27 days. Usually more between 24-26 days though and I am pretty sure I ovulate either earlier than expected or later.

So my most recent period was August 8th and it lasted two days. So August 8th and August 9th. I do not know when I ovulated. I got multiple very clear positive pregnancy tests beginning September 2nd.

I may sound stupid but I’m just not good with this kind of stuff. Can anyone help me figure this out?