I wouldn't stress too much. With technology today they will be able to tell if your baby will be too big for your pelvis and can arrange for alternate arrangements regarding your birth.
I was born 7lb 10oz
DH- 7lb 11oz
DD- 7lb 12oz
DS- 9lb!
Then I have baby to be so hopefully it's not over 9lb cause to tell you the truth that [I]really hurt!

At the end of the day as long as your baby is born healthy, it doesnt matter if it was born vaginally with a comfy fit or by c-section cause it couldn't fit. Good Luck!