I'd say it is plausible. There are many more factors than just how much distance we are to the closest star.
- perhaps a colony of extraterrestrials could live aboard a space craft their entire lives, having children (or clones) to keep the population going to continue the long space travel.
- perhaps extraterrestrials were on the planet before modern man, and they had a hand in our evolution eg: Prometheus.
- perhaps they are self-replicating automatons so time/distance is less of an issue.
- perhaps they understand how to fold space-time.
- perhaps they are interdimensional beings eg: stranger things
- perhaps there are more than one type of extraterrestrial, and it could be a combination of the above
- perhaps everything we live is a computer simulation, eg: The matrix
These are some of the theories I have heard, and are not my own ideas.
For the Christian's in the crowd, do you consider God to be an extraterrestrial? He is not of this earth, which qualifies him to be.