How real is Harry's response to his impending death?

A friend at work recently read The Half-Blood Prince and The Deathly Hallows for the first time. I know: amazing to think that anyone out there hasn't already read all of J.K.'s novels!

This friend is a highly intelligent, quite thoughtful man who has an interesting way of seeing the world and whose opinions I respect. Thus, when he made an offhand comment that he felt that Harry seemed a little too mature in the way he faced his death in the final novel, I felt I had to take this comment seriously

I asked him to explain what he meant. He pointed out that Harry, at that point, is merely 17 years old and, despite his rather event-filled life, it seemed hard to believe Harry would be able to 1) accept the fact that Dumbledore had been planning for him to die right from the start and 2) face his death with such seeming equanimity. It's an interesting point.

But also one with which, having considered it seriously for several days now, I find myself having to disagree. I don't think Harry's behaviour at that point belied his tender age; I think it spoke volumes about the depth (and depths) of his experience. Harry might be 17 at that point but, by then, he had suffered more in his life than most people do over their 80 years on earth.

I won't recite here all the challenges he's faced (anyone who would spend time reading a Harry Potter blog is already fully familiar with Harry's life-time of tribulations and suffering) but I can't imagine that the Harry Potter I know so well after reading his exploits in those seven books responding to the situation he is presented with at the end of Book Seven in any way but the way he does.

Harry is not entirely without emotion in these scenes; in fact, he mentions numerous times how difficult he was finding it to drag himself away from this friends and the fight. But he finds his strength with the Resurrection Stone and the four people who have been together for so long, first supporting each other, then him since they met at Hogwarts years before.

I actually find J.K.'s depiction of Harry's mental state at that crucial moment to be entirely convincing. It is absolutely real for me, right down to the maturity with which he faces his impending death. It is true to the soul of this young man that he would choose to walk into the woods and face his death once he realises that he must die to protect his friends and loved ones from further harm. I still respect my friend and his opinions; I just disagree with him on this point. Very strongly disagree, in fact.