Every human on earth has gained imortality
every human that is EXCEPT YOU!
Consolations! You're not immortal. No, you don't have a choice. You will eventually die. You regenerate at your regular rate from all injuries. You feel the same levels of pain and your mental state will deteriorate naturally. Also, you will age. Are there any other things people generally use to pick holes in this sort of thing? No? Good.
You must choose one other who will lose thier immortality to join you as the only other person to age and die under the rule of your new undying overlords. Who will it be?