SHOULD I LET MY OB SCHEDULE ME FOR A C-SECTION, OR SHOULD I TRY ALL NATURAL?

Marge
This morning I had my last ultrasound(37 W+2D), baby is measuring 7lbs and he's already in position to get out, only 19 days left. My concern is that I don't want him to gain any more lbs. I had a C-section 6 years ago, but this time I want to go all natural, I spoke to my OB 2 weeks ago that I want to try it, and he tells me no because I have Gestational diabete he has to schedule me for C-section, I said no, at least let me try then if I can't, they can pass to plan B ( emergency C-section). What do you guys think?