What your fundal height is doesn't mean the baby is big, doesn't mean you'll go early, remember it's measuring your uterus not the baby. My son was 9.7 lbs and I never measured ahead.
Did you have an early ultrasound to determine how far along you are? My OB told me that is the most accurate predictor of due date. Once you get past about 12 weeks the size of the baby or your uterus don't determine your due date.
With DS, I almost always measured ahead. Like, 2 weeks ahead regularly. Besides other issues and because he was 97+ percentile, I had several u/s to keep checking. U/S can vary dramatically, especially as you are further along in your pregnancy. My little guy came a week early and weighed a little over 7 lbs. Don't worry too much about it!
Re: Measuring ahead?