Here are the ways I am an old man.
I have matching pajamas and an monogrammed robe.
I wear Florsheim leather slippers.
I smoke a pipe.
I shave with a double edge safety razor like grandpa used to use.
I prefer classic cocktails,e .g. Manhattans.
I don't really like "cool" movies or music. Give me some Dean Martin anyday.
I'm sure there are other ways, too. Look for an old man update if I think of them.