changing due dates?

Mizsoccer83

I am a FTM and my original due date was changed when we had our first US at 7 weeks. It went from August 5 to August 13. Since then, baby has been measuring on target. We had an elective US done at 14w6d and baby was measuring at 15w5d. Today is our a/s and if LO is still measuring "larger" than the weeks I am currently-will they change the due date? This is all new to me, so I am not sure. TIA!