You might not be permitted to serve on a real jury.
Although there is nothing wrong with your reply that you are uncertain of whether you could impose a life sentence, the defense attorney would probably argue that since you lean towards the death penalty in all cases, you would not make a decision on the facts but upon your personal belief in the death penalty and you should be excluded from the jury by the judge. On the other hand, the prosecutor in the case would likely argue that you would be able to decide the sentence by listening to both sides since you have not finally made up your mind. The prosecutor would probably want you included on the jury. Both the prosecutor and the defense attorney would probably ask you further questions to see how deep your reservations about a life sentence go.
To find out which answers would allow you to serve on a jury go back and choose each different answer.