about I-485 ( I was born in main land China )

My NIW was approved in Sept, and it took less than one month. I am a post-doc researcher in a University. If I stay in the same position, is the chance of my I-485 100% ? As I know, the processing of I-485 is basically security check and background check. As I understand, so long as my background is good, it is only a matter of time for me to get my green card (of course after the cut-off day passes my priority day). Could any one kindly tell me if my understanding is right or not?

Thanks a lot