Excellent news! Congratulations. I've blogged before about studies showing that ultrasound measurements can be off by up to 4 or 5mm so, really, measurements are not at all concerning here.
Everything sounds great. Going to move you to the Misdiagnosed board because we get a lot of women here after IVF who are misdiagnosed. Because doctors are certain of dates, they tend to act hastily when measurements are off.
Please, keep us updated!