Yeah, empathy in general should set in a LOT sooner than 25. But I think there's a certain kind of empathy that develops when you understand that you're not bulletproof just because you're the center of your own consciousness, you could actually die--and therefore other people can, too. I worry about my mother's safety--say, on the road--more than I ever did as a child or a teenager.

To bring it back to Harry Potter, a lot of the practical jokes James and his friends play seem to point to that lack of mortality-empathy--not understanding that people can actually get hurt. They would probably, begrudgingly admit that it's a crappy thing to do, if called on it, but if someone had gotten killed because Lupin wasn't safely locked up, they probably would have been genuinely shocked. Pranks aren't supposed to have consequences, you think, when you don't have a sense of mortality.