Is DR/BDR election is preemptive?

The DR/BDR elections are not pre-emptive.So first thing that happens is a router will listen to the hello’s and see who else is out there.

If nobody there, then it asserts itself in position. If there someone else at the same time, then they’ll either challenge (better info) or acquiesce.

Even if the one who comes in first here has a crappy priority/RID, it is still in place. And even if your star router comes in next, nothing will occur until the others go away and an election takes place.