Voluntary induction at 39w

My pregnancy 2 years ago I did not have GD. Baby always measured around 80%ile and because I showed no signs of labor, I was induced at 40 weeks 5 days due to my history of IVF and prior pregnancy loss.

This time, I was diagnosed with GD and pretty well diet controlled. Baby has still consistently measured between 96-98%ile. At first my OB suggested I be induced at the end of 39 weeks, As close to 40 weeks as possible, if my blood sugar levels were under control, which they have been. Now she’s suggesting inducing at the start of 39 weeks because baby is measuring big. I’m worried if I’m induced that early, that my body won’t be “ready” and I’ll have a failed induction resulting in a c-section.

If you have been induced at 39 weeks or if that’s the plan, what was your doctor’s reasoning? Do you wish or will you push to wait closer to 40 weeks?