Physically stronger, obviously. Mentally stronger in terms of intelligence, since I'm evidently more articulate and well-read than I was a few years ago. Though I don't know whether I'm so far ahead of my own age group as I used to be; I think that going to a rubbish school and being held back to some extent has caused that gap to lessen. But of course, that's what the schooling system wants; everyone to be brought to the lowest level rather than everyone raised...
I think I'm psychologically weaker, much less self-assured than I was, something which I think come with exposure to the world. If I imagine myself ten years ago, when I was 8, I was quite confident, confident in a lot of things - in the world, myself, in authority figures. But when you become more experienced you learn that things are a lot less stable than you had imagined; policemen aren't the most responsible people in the world anymore, your teachers don't know everything, you can't trust the way things appear.