I plan on living forever. So far, so good.

The humor hinges on logical sleight of hand: immortality is an absolute claim, but the speaker evaluates it with the kind of incremental progress report used for ordinary projects. The line satirizes human optimism and self-deception—our tendency to treat even the most uncontrollable facts (mortality) as if they were manageable plans. At the same time, it can be read as a lighthearted affirmation of living in the present: whatever the long-term outcome, the only evidence available is that one is alive now. Its deadpan tone makes it adaptable as gallows humor, resilience, or simple comic bravado.