Remember, just because your physical age is 80+, that doesn't mean you were born 80+ IG years ago...
Mars years Earth years deal? When on Mars be as the Martians are... and use their calendar.
Game years conversion to real years is something I only vaguely understand. Is it 1:1? But seasons aren't 1:1 and unless BM universe has multiple suns or really complex stuff going on in its atmosphere then that is a bit weird. It is also possible that a BM year isn't just one revolution around the sun.