We don't know how long it takes to evolve our level and kind of intelligence, nor if intelligence like ours implies successful expansion such that it could eventually be noticed from the kinds of distances we can sense with our tech, nor how fast it would actually expand.
If the first in any light cone dominates that light cone, expanding at a high fraction of c, then almost everyone starts off thinking they're the first.
We may be the first in our own light cone, and that light cone may be just about to start intersecting with that of a galaxy where every star has been completely Dyson'd by a Kardeshev 3 civilisation.
If the civilisation is two million years older than us, that galaxy could even be the Andromeda galaxy.
No, it actually seems to be the most likely explanation. The universe is so young yet. It's just a cosmic blip of time since the current generation of stars has began forming.
Someone has to be first (in our speed-of-causality bubble), maybe it's us?