Completely normal. Just go by the due date they give you and not by measurements. My little guy has measured ahead and behind and so have both of my girls. I always stick to the first due date no matter what!
I just came from my 20 week appt with my doctor and he said anything in a 2 week window either way is considered normal. Baby is measuring a week ahead for me.
I was the same . I went into my first ultrasound thinking I was 18 weeks 4 days, but she told me I'm actually 17 weeks 6 days. This was April 24th. We'll find out what we're having may 11th ❤️