A disturbing realization

I made a disturbing realization this evening.  A young guy I know was trying to locate a mistake his 16 year old son had made.  Ignore that part of it, the mistake is irrelevant. Think about my perception of a young guy with a 16 year old son.

If I perceive mid-thirties as young, then that make me ... older.

I might have been him 20 years or so ago.