Yes, it is quite amazing, the willing to learn of these young girls and guys! I can compare this to my own students here. I remind them sometimes the luck they have to have all this knowledge offered to them on a silver plate.
In terms of spread, I agree too. The class in Nigeria is really spread out in terms of age group (13-17, learning the same things). I also found interesting that the brightest students are often quite young, but that's probably a faulty correlation due to the small sample...
I am glad you had such a great time!
Yes, we must be careful with statistics. Especially in such a school where the selection has been made including many diversity criteria (sometimes predominant).