The reality of a species reaching interstellar travel will be any other species will be dozens of millennia of years ahead or behind at most.
This of course doesn’t allow the allegorys that trek is famous for.
If we spread to an neighbouring star system then we can spread to 50, then I don’t see what will stop them from continuing to spread, to the point the whole galaxy is occupied by future mutations of humans, or solar systems completely drained of resources.
But I don’t see humans having the drive to actually spread beyond Earth before the end of modern human civilisation (be it war, plague, ai or technological regression)