Is it possible to come up with an unprovable/undisprovable scenario of a past civilization many years ago? Yes: they lived >55 millions years ago so artifacts are gone due to a full tectonic convection cycle causing all the artifacts to get melted. They also could have developed organic technology, and used it to erase the non-organic waste of their past.

I love the idea, it's amazing to think about. And it might be true.

However, we can't prove it, we can't disprove it, and it has no bearing on our current state. In the absence of evidence I've got to try to apply Occam's Razor, so the simplest of competing theories should be selected as the one to go with until/unless evidence shows otherwise. Which means we should consider humans the first advanced civilization on Earth until other evidence is found.