I think that the hypothesis proposed in this article sounds like it's certainly a part of the effect we feel, but there is likely some support that the percentage of our live thus far that each moment adds up to plays a role in our sense of time passing as well.
Think though, to your novel experiences later in life and how time passed. I can certainly say that even though just recently I left Canada (my home country) for the first time, to go to Mexico, I can recall every second of it, and it did seem to take a long time.
So I would argue memories are encoded based on what is perceived, and I think we perceive what is most important to us at the time. This is often something we are learning; something novel. Routine is not encoded carefully because it is not important to us. We aren't learning anything new when we follow our routines. But when we experience new things, we are learning. The density of the memory at this time gives a prolonged time passage effect I imagine.
There is a similar psychological effect: Think in terms of your closest acquaintances or, better yet, a new love interest. Because you spend so much time with them, getting to know them, you encode a lot of memories that involve them, and so when you are apart for a short period of time, it seems like much longer. This is quite noticeable after a break up, when you're time with someone goes from very high to zero.
Those are some of my thoughts anyhow.