What kind of twins are you having? I learned that the type of twins makes a huge difference. We're having di/di twins and they pose the least risk of all twin pregnancies. It's basically just like having 2 singleton pregnancies... they just happen to occur at the same time.
We do weekly stress tests to make sure they're still handling the pregnancy well & they pass with flying colors... they're typically done within the first 5 minutes of starting the test. I also had frequent ultrasounds (though not as frequently as other, higher risk twin pregnancies) to make sure they were growing adequately and they look great. At 35 weeks, they were both pushing 6lb.
I also think it helps that I'm healthy & have had a complication-free pregnancy in the past. Low BP, no diabetes, healthy weight, a previous pregnancy that went to 40 weeks and was delivered with no complications... it all puts me in a better position to carry this pregnancy to a healthy date.
We talked about induction and all that a few weeks ago and the OBs at my practice all agree that they see benefits to keeping babies in up to 39 weeks. Every week you can keep the inside, they get bigger & healthier but 39 weeks is kind of the point of diminishing returns. They don't see enough benefit in terms of growth of the babies to warrant the discomfort of the mother (and woah baby, am I in a lot of discomfort!!).
I've got one friend who had an OB that always scheduled c-sections at 36 weeks for twin pregnancies. After seeing her tiny little 5lb'ers in the NICU, I'm really glad that my doctors take a more hands-off approach to the pregnancy.
Congrats to you, though! I hope these next 17 or so weeks are healthy and comfortable for you!!