Congratulations on your pregnancy! Remember due dates are an estimate. Like you, I always knew my dates of my lmp. My 4th child was born at 36 wks weighing 8lbs and 21.5in long. Everyone freely voiced that my provider must have had my dates wrong. My dates were right, my baby came when she was ready...my provider was a midwife and she trusted that I knew my body. (My husband was also home from his mid-tour from Iraq and we had a 2wk window where he was home...there was no mistaking when our baby was conceived...my lmp dates were accurate.)
I encourage you to watch The Business of Being Born documentary by Ricki Lake & Abby Epstein. You can rent/watch it through Netflix, if you have it.
I encourage you to read "The Thinking Woman's Guide to A Better BIrth", by Henci Goer
I encourage you to HIRE A DOULA!
Congratulations again...and remember it's your body, your birth and your baby...Trust the process & Trust Birth
Peace & Light,
J.