To make a long story short, I don't think, I know.

There are actually far, far more than a billion stars.   There's something like 10 billion galaxies in the observable Universe and roughly 1 billion trillion stars :)

Yes. tough sometimes I think that we might just have happened to be the fastest to grow, in the end that dozzen bilion years that separates us from the Big Bang might just be a blink in the history of the Universe so there might just be us...
The thing that bugs me the most about Aliens is that even if they are out there, they might just not develop a mentality/natural behaviour similar to ours. let's say that there is this very one planet where life has formed but where there is only 1 species: this species rules the whole planet and since there are no other species competing with this species, they aren't endangered----->Evolution isn't needed for them to proliferate ---->they won't be able to reach evolution levels that permit to traver trough space.
Another interesting assumption that could be made about said species is that, since they are the only beeings on this planet, even if they were to evolve, they'll probably not need the feeling of supremacy or needing to conquer something, meaning that they'll probably never be interested in space exploration...

They only question that should be asked is: how much more advanced than us are they?.

I would not even be surprised if they 'fly' around here. A lot of people come with all the science (that we humans know) explaining how it's never possible for them to come here. The distance is to big, physically it's not possible, and all that nonense. All true for us humans and our understanding of how things work (which is like almost nothing).

But it's not to hard to imagine that if a species is, lets say 50.000 years, more advanced than us that they figured out how our universe (or the multiverse) works and can travel freely through it.

Its a mathematical certainty. Even if you do not for some crazy religious reason, ask yourself if the God you believe in would limit the ability to create life to a single planet among a near infinite quantity of planets?