I specially want to use this word after "adolescent" . better said, I'm looking for a nice paraphrasing for " young people ".
A bevy of adolescents or bevy of youths means a group of young persons. Not exactly the kind of construction you're looking for, but it would mean the same as "an adolescent (word)".
"bevy", used most frequently with girls, women and children. I've also seen it used with reference to sailors.
'battery' is a term used for group of people, usually soldiers - but it is not restricted to soldiers. It can be used for young people - 'charged' with lot of 'energy', I would presume.
might the word be moxie: a moxie adolescent.
A few informal and humorous terms for groups of young people
My personal favorite being:
gaggle noun a group of people, especially a noisy and uncontrolled group
but then there are these:
bunch noun a group of people
gang noun a group of friends, especially young people
mob noun a group of people who are connected in some way
crew noun a group of people
clan noun a group of people who share an interest or goal
bevy noun a group of people or things of the same kind
lot noun a particular group of people
posse noun a group of friends (This word is mainly used by young people referring to other young people)
from the MACMILLAN DICTIONARY
A group of people from the same generation (of same or nearly same age) are called a "cohort".
Free Dictionary COHORT Noun 1(c) A generational group as defined in demographics, statistics or market research