Pregnant amino testing

Patient: Am 48 and pregnant naturally, I have gestational diabetes,which I take 3mg of Gyburide at night for. My BP is usually around 100/60. I have gained 26 lbs and am currently 35 weeks. My doctor wants to do amino at 37 weeks to check lung development. She keeps mentioning stillbirth. I have non-stress test twice a week and ultrasound once a week,two days ago my fluid levels was at 12. What is your thoughts on if I need to do the amino? And how much more of a risk is the baby for stillbirth if I wait until 38 weeks and 3 days? My thoughts are if stillbirth is at high risk at after 37 weeks then wouldn’t it be better to go ahead with the c-section no matter what and treat him if lungs aren’t ready when he’s born? And how accurate is an amino for testing lungs?

Doctor: