Microsoft Contract offer & FTE Pending

Hello, I recently got a Microsoft contract offer right before Thanksgiving that I accepted over the phone because I was so excited and got ahead of myself. I did my final panel interview for the Microsoft FTE position on November 11 and have been waiting for their decision since. The contract position has already sent me the background check and acceptance letter on November 25 but I've been trying to hold out on any docuements before I hear back from the FTE. Now my recruiter is really pressing me to get my docuemtns signed to begin the onboarding and asked if I was stringing them along. Should I just start with the background check and hope I hear back from the FTE this week?