In the second to last sentence should that be realized? I don't like how that sentence flows. I personally would make it "They hadn't realized that life would pass them by" only because that "you" throws it off from the rest, Unless maybe you did
They hadn't realized "Life shall pass you by."
as if it was a quote.
I liked reading it this, it wasn't to detailed to put an image in my head, it let me create one,