Yes, logically, the cause must be eternal. Otherwise it just doesn’t make sense.
Is it inside or outside the universe?
Outside, since it is from before the universe.
Is it visible or invisible?
Existing outside time and space and light, it is invisible.
So to summarize: The Universe has a First Cause that is eternal, outside the universe and invisible to human eyes.
Now it is important to think further about the nature of the Cause. Is it an impersonal force or does it have some sort of intelligence and personality? Is is a something, or a someone