My second hypothesis is that it may be easier for someone who is younger to use TrackIR more intuitively (in my own case, as soon as I got all of the settings right, before I even scaled everything how I now like it, I immediately caught on to TrackIR and found it extremely natural- I'm 15).
I'd imagine that for someone who has been exposed to virtual 3D environments from an earlier age, it may be easier to detach yourself not only from your surroundings but from your own physical movements and the expected result of those, becoming more immersed in the '3D' environment, and easier to take to equipment like TIR.
However with your age I think my second idea may be bunk as well 
It's probably just a personal thing with no real cause.
HOLLY POOP!!!!!!!!!!!!!!!!!
Motherland you are only 15?????????????????
wow to have read your postings in other threads i never would have guessed it, you are very well spoken generally more respectful than others and intelligent>
if there are more like you at your age out there in the world and you are not just some kind of mutant that will be hunted down and destroyed by the moronic manikin masses that seem to be the prodominant strain of todays youth, well then maybe there is a hope for tomorrow!
<SALUTE> to you for being the person you are! and good luck in all of your endeavors through life!
but i do believe that your second hypo does hold more water than you think. beginning in your mid twenties your body starts its inevitable decline. so being in his thirties his eyes and the muscles in his neck and upper back have already begun to stiffen and decline. now he is tasking them in new ways, they will take time to rebuild the muscles and the mental responses to use them in a coordinated manner to gain the effects sought. it will take practice, like any other new skill for him to become really proficient with it.
he has been playing a long time, but in a 2d environment. he has grown into the pattern of looking at things in one manner and now must relearn them in another. it will take time for him to first forget what he thinks he knows and then to relearn everything from a new perspective. for younger people, such as a teenager this is a faster and more proficient transition, than it is for someone who is older and more set in their ways. the biggest hurdle will be the mental one, once that one can be retrained the physical transition is nominal.
dont be so quick to cast aside your hypo's, your a more intelligent person than i think you are willing to give yourself credit for. dont sell yourself short because you are humbled by your age in the eyes of others.
<SALUTE>
