Baby Age Not Sure

Hello po. Kakatransv ultrasound ko lang po. And then lumitaw sa age is 6weeks. The last date of the first day of my menstruation was July 23 po. Calendar method po kasi ginagamit naming mag asawa and I even recorder na August 1 kmi nag do. Nagtataka lang po ako ilang weeks na talaga si baby ko. Thank you po sa sasagot☺️