What if I accepted the fact that I'll die of old age, and decided, after evaluating the arguments pro and against, that it's the best outcome for me?

Then thats how it is.

However, when someone reevaluates a long-held position, even one which was developed and maintained for manifestly irrational reasons, they are still extremely unlikely to change their mind. If someone claims to have evaluated such a position thoroughly, it is generally a good bet that they stopped thinking once they found a good enough justification of their previous belief, before there was any real risk of changing their mind. This is a central topic in the sequences.

Of course this is a bet, not a certainty. I don't mean to be harsh, but you should seriously consider the possibility that your argument is a rationalization. orthonormal's comment is probably more helpful to this end.