We're young people, so let's dance madly (11)
I believe the answer is:
adolescents
'we're young people' is the definition.
'so let's dance madly' is the wordplay.
'madly' is an anagram indicator.
'so'+'lets'+'dance'='soletsdance'
'soletsdance' anagrammed gives 'ADOLESCENTS'.
(Other definitions for adolescents that I've seen before include "Youths" , "Teenagers" , "Kids" , "Young people" .)