If you're not mentally ready to go this is hands down the best question

"You can't. You had literally all of eternity to ask your final question, you could've used some of that time to come to terms with your death, but instead you immediately used up your question(and your remaining time) trying to cheat death. Goodbye"

You cannot.

[fade to black]

Well, you could in theory build as accurate as possible a recreation of both yourself and the entire universe in simulated form that wouldn't be dependent on a body with an expiration date.

You wouldn't have much benefit from this, but the copy would benefit a lot.

Unless...you already are that copy.

(There's actually a group in antiquity that claimed this was the case - that souls which depend on bodies are screwed but that we all are actually copies of a first humanity which brought forth an intelligence in light which tried to save them, couldn't, and thus recreated them within its light in a copy of the universe. That it's actually the future, we just don't realize it, that the evidence for this can be found in the study of physics, and that those who understand its sayings about it being better to be a copy of what existed before will not fear death.)

You can't, you need more time.