Congratulations! You're now immortal. No, you don't have a choice. You just cannot die. You regenerate almost instantly from all injuries. You feel numbed levels of pain and your mental state doesn't deteriorate. Also, you will no longer age at all. Are there any other things people generally use to pick holes in this sort of thing? No? Good.
Simply, you're immortal. You have the ability to make one other person and only one other person immortal. Same deal as you. Just the two of you, forever.
Who do you pick?
My answer is quite easy. It's Quin. We've discussed this before. I would pick Quin.