Change due date !!confused!!

Jaquisha

My second ultrasound but the first one i got to keep sooo i was thought n was told i was 6weeks n 6days as of today but i went to check on luvbug and i was told im actually 6weeks and 4days im due june 19th 2022

*my last period was September 10th so should i go by my last period or by what the lady told me today at your choice pregnancy????*