I have found a galaxy closest to ours the Milky Way, and similar only ten times bigger. It is called J0107a. If you look at the skies at night at 12 pm, it is a little left for the moon, "Cetus". It is 11 million light years away. So I`m thinking, since modern humans are 300,000 years old, aliens then have never even started the journey towards us after they for example picked up on our radio-signals.. If that is even possible with the distances in mind!
I don't know if life can exist anywhere else than in a galaxy similar to our own, but I assume intelligent life must have something similar. Since again, J0107a is ten times bigger than ours, I was thinking maybe it has 2-3 planets like ours, not just one. If they knew where we were here 300,000 years ago, then it's nothing compared to the 11 million light years it takes to travel here
There are way too many variables (unknowns) right now for us to be able to accurately calculate how common, or not common, life like us (or more advanced than us) is right now, but a lot of scientists are working on it though.
As for life more advanced than us, while probably possible, even in our own galaxy, a lot of other questions (unknowns) come up also, like why we've never seen them, or heard from them, or had any contact with them/from them, and whatnot, etc, only furthering the problems in calculating how common or not common life like us (or more advanced than us) is, etc, I hope they find out more in my lifetime though, as it's most certainly a subject I am greatly interested in, but right now though, there's too many unknowns right now though, etc.
Might want to look into the Drake Equation if you've never heard of it, etc.
Also, I think the closest galaxy to ours is Andromeda that is on a collision course with ours soon, unless I'm mistaken about that, and I'm not sure how big, or how far away it is right now (but it's very, very easy to find out/look up, etc) and about it being on a collision course with ours "soon", I think it's four or five billion years or so, or something like that, so we've got some time before that happens, and our sun might make the earth uninhabitable before then, etc, but either way, a lot of this is still a long ways off still, so we've got some time still, time to evolve more and spread out from here maybe before that happens, etc.
As for how old homo-sapiens are, I think they are probably just as much approximately old as science says they are, or is, etc, but that Adam and Eve, and their very first descendants before a local flood wiped out most of them around 6-7 thousand years ago, were specially created/made by YHWH around that time, and were of what I have termed the homo-divinus species, around 11 to 12 feet tall, and perhaps having some more advanced knowledge than the homo-sapiens of that time (agriculture, building construction, metallurgy, advanced pottery-making, etc), and that started running into geographically and interbreeding with some of homo-sapiens that existed at that time, which is why most of them were wiped out by a localized flood at that time, and turned the once very lush middle-east into a desert due to some salt water being introduced at that time, and other things like that, etc. We're all hybrids now basically, or most of us are basically, etc. Still have some of that DNA/blood left, although it's not very much, and has been greatly diminished since that time, etc.
Anyway, God Bless.