Amnio 36 weeks for lung maturity?

I am having an amnio today to check and see if my daughter's lungs are developed. I am scheduled for a c-section in two days. I have gone into pre-term labor three times, and have had several complications with this pregancny. My son was born at 35.5 weeks and he was totally healthy. Has anyone had an amnio at 36 weeks? What was the outcome? I am just a bit nervious that her lungs won't be developed :(