How do I calculate how many weeks I am?

My last period was the 22nd July. I took a test yesterday and today. Both positive we’re so happy but I just wanted to know how to calculate how many weeks I actually am. Everything asks for an average cycle length and I have no idea what mine is. I’ve had 2 cycles which were 27 days and the last one was 34 🤷🏻‍♀️