Could my due date be wrong?

Sa

Long post, but I’ve always felt my due date was wrong. My last period before my BFP was super light and only 2 days (usually they are heavy and about 7-10 days). I got super dark lines almost a week before the next period was due. Original due date was July 6 (based on the super light period), but they changed it to June 28 after the first trimester ultrasound. At my 24 week appointment, my fundal height was measuring 27 weeks. They did a growth scan ultrasound at my 28 week appointment, and baby is almost 4 lb. Baby is also already head down. My fundal height at 28 weeks was measuring what should be 33 weeks. I’ve never really believed the due date to be accurate. I asked my OB if they were going to change it again and she said no, but that doesn’t mean baby won’t come earlier. Do you think my due date could be wrong?