I am 54 years old, and the parties I dj range from elementary school to senior citizen events.
here is how I find modern pop dance music.
look at the top 40 chart.
play each song.
if it sounds like a dance beat, it goes in the opo dance folder.
if it is a good song but not danceable it goes in my modern "cocktail hour" folder.
if it isnt either I skip it and go on.
maybe 20% are danceable, maybe 40% are good for background music.
this is how I find music for any era, and any genre.