This just isn't true. Nobody cares, but everyone is probably closest to people their age. Most my friends at work are about my age (or at least how old I look)

This just isn't true. Nobody cares, but everyone is probably closest to people their age. Most my friends at work are about my age (or at least how old I look). This is obvious because of our career stage, which advances steadily with age. 99% of my personal friends and professional network are my age +/- 5 years, thanks to research / conference experience and career cohort effects. When I look ahead to those jobs I hope to have, most of them are 45-55 and have peers in that age range as well.