What due date?

Sh

My ob has never told me my due date ao I'm a bit confused on which to go by

1) first appt supposed to be 6+5 but measured 6+1

Baby has caught up now. So...

2) today's appt supposed to be 11+3 but measured 11+5.

Do I just go by lmp and original due date? The days aren't terribly off. But I never thought to ask.