Is there a bad thing on eternal life in your opinion, even if its just your own one?
Yes, for the reasons gjd800 outlined.
Do you think that immortality begin to bore you after a while?
Yes.
Would you do a crazy thing, if you know that you can't die?
No.
Is that rather a superpower for a hero or a villain?
A superpower for a hero, I hope!
Do you have still a fear for anything, if you can't die?
Yes, the fear of seeing everyone else die.