On Earth, there have been previous life-forms which have died out, there have been more or less intelligent life-forms which have died out (various dinosaurs and exhausted branches of hominids etc.), there have been previous civilizations with varying scientifical/technological achievements; but there has never been a species on Earth which has created a civilization as advanced as humans have.

So, we are the first ones to reach this point on the Earth. Not the first ones ever, but first ones to get this far.

If we assume the patterns of evolution observed on the Earth are nothing specific to Earth and they repeat throughout the Universe, there are/have most likely been life-forms (simple and complex) of varying degrees of intelligence, as well as civilizations of varying degrees of technological advancement.

However, since we apparently see absolutely no trace of anyone else, either they failed to successfully bootstrap their colonies outside of their home planet/moon, or we got here first. It's unlikely, and absence of evidence is not evidence of absence, but someone has to be the first. Maybe it's us, from our little blue planet.