that is not at all true. i was very much a mediocre runner in high school, most likely because running breaks my body down very quickly and i couldn't put any miles in without getting hurt. skip ahead to my 25th birthday when i started actually training on my bike, not because i wanted to race, just because i love exercise. i got pretty good pretty fast and people noticed and encouraged me to race. so i did. and i won my first cat5 race, consisting of just two 16mile laps with 1500' of gain per lap, by over five minutes after attacking at the base of the climb on the second lap. and yet, my freakiness lies in my anaerobic capacity, which i truly never knew. looking back i can see it went unnoticed, as i used to be able to do upwards of 50 pull-ups and well over 100 push-ups when i was into that sort of thing.
so, again, a freak is a freak and it's not something that can be taken away from you, nor do some freaks ever realize their true nature
just the same, odds are that the OP isn't a freak.