as long as u r married before

as long as u are married before your 485 approval, all is well. You don't have to wait the average 4+ years.

If you get married and she files for GC before your 485 approval then she can either
1)comes to the US on H4 and then file 485 or
2)stay in China and wait for CP

If you get married before your 485 approval, but she files after you already got your GC, then she can use "follow to join" option because she can no longer be "added on" to your pending application.