Early scan dating (CRL) is usually more reliable than counting weeks from your last period. A 1 to 2 week gap like yours is common and isn't a sign of a problem with your pregnancy.
Next Steps
Your screening test result already uses the scan-based age. Go with your doctor's CRL dating rather than the LMP date.
Health Tips
If your dates keep drifting apart by more than 2 weeks on later scans, ask your obstetrician to review the dating.