At age 17 I made friends with a coworker in their 40s. I found out he was into D&D and he invited me to sit in on a game. Now I'm 30 and I been playing with this group of now 50-60 year old dudes every Sunday since. Age gap isn't strange but if your getting weird vibes maybe have a chat with your son about your concerns, but he is an adult in college now. He will likely have many connections of all ages.
I usually see people who can comfortably save and invest as middle class. If you can only barely save or are paycheck to paycheck you would be working poor.
Yeah he and his wife both have a teachers pensions, so what? They earned it working as teachers their whole lives. We should bring real pensions back for every American anyway, not this 401k shlock.
Are you completely financially secure? If not work on that. If you are, find something to volunteer for and give back to society, help your local community prosper.