I can relate a bit to this!

when I was 36 weeks, I went in for my last jab of blood stuff (as I am -blood group) and the MW noticed how swollen I had become.
From there it was like a whirlwind, more BTs, a growth scan and foetal monitoring for the rest of the day, all because my fundal measurement was 44cm (ie, they told me I was measuring waaay too big for that stage) they ruled out polyhydramnios (too much amniotic fluid) then thought they should do another GD test (but they never did) at the growth scan the sonographer said, yes, hes big, but not huge. The problem was that I was huuuge!

Jacob was born at 40 weeks and was 9pd 10, I was induced due to prelabour going on for 2 weeks or so and the OB told me straight up that she thought Id end up with a ceaser.
I did, after 10 hours of labour after AROM, and then put on syntocinon for 4 hours, I just didnt dilate.

I am probably your height but a bit stocky, DP is tall and solid too, BUT they do say that babies take after the mother in the beginning so they CAN be born.

oh, just remembered, my cousins GF had a 12pd little girl last year, VB (with drugs!) and she is tiny, skinny little thing, she also had GD. but wasnt diagnosed till afterwards.