Andie, I had the same as you except mine was 2cm from the cervix but nobody gave me a grading either. From what I read, I think it was about a 2, but no doctor actually said.

My ob at the time preferred it to be 5cm away, but I know some obs are happy to let you birth vaginally with it 3cm away. My understanding is that as you dilate, the risk of cord prolapse or haemorraghing is there because the placenta is still in the way.

I was booked in for a c/s at 38.5 weeks and a scan at 37 weeks just to make sure, however I went into spontaneous labour at 36+6 so missed out on the scan and ended up with emergency c/s.

Sorry I don't think my post answered your question much but just wanted to say good luck on Friday and fingers crossed your placenta moves out of the way a bit more so you can have the birth you want! xox