B1
in the middle of your life before you are old
Dictionary examples:
The middle-aged teacher tried to use slang, but ended up confusing everyone. (0.0)
The middle-aged boss thought 'LOL' meant 'lots of love' in work emails. (0.0)
The middle-aged parents tried to be cool, but their kids just rolled their eyes. (0.0)
a middle-aged couple/man/woman (62.0)