"the best use of the term cannot include a starting point within the boundaries of time."

And that's precisely the point -- eternity is (also) now as omnipresence is (also) here. As I said, I'm sure you see the implications.

"faith that one will go to Heaven at death"

However, despite that faith you may not end up in Heaven as is written in Matthew 7:21. Hence, if I take your beliefs at face value, you cannot know and be sure "on this side of the grave." So, without a "hands-on" knowledge can you really testify that that faith is a surefire way to bring you to Heaven? Moreover, if you, per chance and despite that faith, don't end up in Heaven, are you still saved here and now?