Well, depends on if you are talking about "heaven" proper, or the "kingdom of Elohim" which in one of the 4 gospels is referred to as the "kingdom of heaven".
I personally prefer to the "kingdom of Elohim" as being different from "heaven" proper.
You can be a U.S. citizen, and not be physically in the U.S. for example.
If you "ascend into heaven" per Y'Shua, Enoch, Elijah, etc, I believe this means you are actually THERE.
If you are in the "kingdom of Elohim", then you are a citizen under His government, and you can be in that state without actually being IN heaven.
"The kingdom of Elohim is at hand."
Meaning "within reach", right now.