Do you mind if I ask what your BMI is? There's a big difference between pregnancy with a BMI in the 40s and a BMI above 50.
My starting weight with all three of my kids was 260 - at 5'5", that's a BMI of 43.3, and I also had no co-morbidities. I had perfectly healthy pregnancies and perfectly healthy kids with all 3. With my first son, I was borderline GD, but I monitored my blood glucose levels for about a month and they were fine, even without making major changes to my diet. They were all born at healthy weights - 8-4, 8-3, and 9-2. My husband and I were 8-14 and 9-10 when born, so that was about where they'd have been anyway regardless of any GD issues.
I did have 2 miscarriages and some fertility issues between 1 and 2, but after testing I found out that I have a blood clotting disorder called MTHFR that was probably the culprit. I got pregnant pretty quickly and easily with 1 and 3.
After all that blah blah blah, I say to go for babies now, surgery later. If your doctor is telling you that your fertile time may be running out, listen to him. Surgery will still be there in a few years - your fertility may not.