Thats a good observation though God made the heavens before he made man and before man wrote any scripture so this new place could already be ready or like you said still forming let's say like Alpha Centauri a younger galaxy than ours or this place might not be even in our universe. Or this place could be in our own solar system say Mars once the sun gets to a point in its growth it reaches the red giant stage earth will be too close and Mars in the Goldie locks zone. all just amusing speculations of coarse lol 
The universe came before man, but also Jesus said, I go to prepare a place for you and when it is ready...
However, God speaks as though everyhing had already happened - like, the lamb slain FROM the beginning of the world, so it seems like it happened long before we saw it come to pass. He has a way of speaking that is so odd to me!
Gets too boggling to keep on for too long!.
Interesting thought though, that maybe it's in our universe already...that would make heaven hidden from us somewhere in our own universe, which doesn't seem to my finite mind as right since the waters from above were separated from the waters below...however, at the same time, it seems right because the universe is expanding...gotta stop. Too big a bite for me to process!
