Advice needed..Diagnosed late with gestational diabetes at 36 weeks

Hello I had a growth scan yesterday my baby is measuring ahead.. My AFI levels are at 20. I had fasting blood sugar levels of 90 and the they think I have gestational diabetes..

They are talking of possible c section at exactly 37 weeks as my first was a c-section.

Can anyone advice me on how will this affect baby after delivery as am so terrified.

PS- I had 3 hour glucose test at 29 weeks which I passed.. according to growth scan baby is 7lbs 1ounce.