That is to say, we somehow might not believe that we're going to get old, or we might not be able to imagine that we're going to get old some day.
Citiem vārdiem sakot, mēs kaut kādā veidā varam nenoticēt, ka kādreiz būsim veci, vai arī, iespējams, mēs nespējam iedomāties, ka mēs paliksim kādreiz veci.