An interesting question. The consensus seems to be that it is not narcissistic, which strongly makes me want to speak up for the contrary opinion. So yes, it is narcissistic, self-centered, and fruitless, or it easily could be.
I thought we were supposed to be thinking about others. How can I help so and so?
I think this is the key to answering the original question. Jesus taught us that the greatest commandments are to love God and to love one another. Contemplation of our own death could be good if it is ordered toward fulfilling these commandments. For example, I might examine myself and ask “What do I need to do (for God, for others, to make myself holy) before I die?”
One problem with phrasing the question that way is that it is all in the future. It’s about expectations, plans, and some other time – and it lends itself to procrastination. If you are like me, you tend to say “Right now I’m busy, so I’ll get back to striving for holiness tomorrow, or next week, next month, next year, …”
It’s better, at any moment throughout the day, to ask “What should I do right now? How can I give my attention, thoughts, and works at this moment to God and to others.”
That is not to say we shouldn’t contemplate the future. I am a firm believer in thinking through plans and intentions. To make it effective, though, we have to connect it to the present moment.
I like the metaphor of the journey. Let’s say we are hiking up the mountain. We want to go to the summit. We gaze upon the summit and dream about being there, but right now we have to put one foot in front of the other. We need to avoid tripping over that root. Then we need to walk around that muddy patch. When we come to a crossroads, that’s a new opportunity to contemplate our goal. Which way leads to the summit?
So yes, it is okay to contemplate death, but don’t just stand there. Keep moving toward that day.