Elective C-Section...

I'm 26 weeks and was diagnosed with graves and thyroid disease 4 1/2 years ago. I was deemed high risk and this is my first pregnancy with these illnesses. I have high heart rate all the time and I'm scared of the L&D process. I've had pretty long labors with my 3 prior pregnancies and I'm very concerned about this one. My body doesnt respond/tolerate stress very well and my hr easily rockets up 130 and above. I've voiced to my nurse practitioner that I would like to have an elective c section (even though im high risk) and she's trying to change my mind and tell me they're not good enough reasons. I do not want to try to have my baby and endure a long stressful labor to eventually have an emergency c section. I'd like to avoid the stress on my baby and that of myself and body instead of going through all that. Has anyone had an elective c-section? If so how did you go about it? Or has anyone been in a situation that i am in? Please share