The hiring process for a postdoc position in the US
The academic decision clock can run very slowly. If you don't have other options then I'd suggest some patience. There may be a number of interviews they need to have with others and there may be issues about scheduling decision meetings. Lots of things can slow it down.
If you have a specific need to know about the decision then you can be a bit more aggressive in asking, but otherwise, a request for an update after a couple of weeks is probably acceptable. The most information you are likely to get, however, is that you are or are not, still in the running. You can ask whether they can give you an &quot;estimated decision date&quot; and they might answer, but  don't expect it to be especially accurate.
But don't pass up other opportunities as you wait.
I doubt that very many places will tell you that you aren't the first choice and if others are ahead of you they will wait for a decision from one of those before telling others they won't get the position. But don't read too much into a delay, and don't panic. There are too many possibilities.