Everything ages, including the population, and there is little we can do about it short of having plastic surgery or lying about it. There is another way to take a few years off but you will have to figure it out as part of the odd twist in this puzzle. The graph is for illustration only.
Cache can be found at
N 44 (AB).(CDE); W 093 (FG).(HIJ) where;
When adding, use the ones digit (7+6=3).
A new John Adams gold dollar for FTF.
You can check your answers for this puzzle on Geochecker.com.