Aog by lmp : 6 6/7 weeks - aog by scan 5 weeks by gs.. is this normal? which one shud i follow? irregular periods.

Irregular periods: This would be a much easier question to answer if your periods were regular. In general, if you are very sure of your LMP then I would recommend dating based off of your LMP. But since the Ultrasound was performed early in the first trimester I think it would be safe to go with that estimation. As always, you can never predict an exact date but these can be helpful to give you a good ballpark rang