A.S.
My experience wasn't too pleasant. I didn't think about the needle length too much. I'd try not to think about it at all really. The baby moved right up next to the needle and wouldn't budge, (son has Spina Bifida) so we were stuck there waiting for a bit, while the doctor pushed on my stomach trying to get him to move so they could take the needle out. I grabbed my hubby's hand real hard during the procedure, but the pain from the steriod shots were much worse in my opinion. After the amnio I was fine and got right up, but they all came running at me and told me to go slow. Had a stress test right afterward and rest for 24 hrs. We were fine though.
I'm sure the baby's lungs are fine, they told me sometime in my late 20 wks that they were confident he would be ok if born then, (I had the amnio done at 26 wks so maybe it was then), they really like to get to 37 wks, but they didn't take him until 39 wks. Oh, if you're RH- they will give you a shot of rhogam after the amnio, and after birth. Good Luck!