I would argue that while similiar, they ( height and intelligence ) are not exactly the same. Brains have plastiticity to them, which allows some level of calibration and adjustment ( though seemingly mostly intended and used to overcome damage )

<< You may feel smarter now, but are you really?

Best I can tell you is that, looking back, I was definitely dumber:D To your point, that may be just experience talking.

<< What, exactly, makes you fell like you are?

Now that is a good question. I think it is mostly reflection on what was and comparison to what is.

<< Do you think that if you met those same people today they wouldn't still be significantly smarter than you?

Hard to say; life has a way of beating you on a consistent basis and, from what I understand, all 3 have kids, which bring their own challenges ( you certainly can't pursue what you want to pursue as easily ).