juvenile vs preteen

juvenile and preteen both are nouns.

Word	Noun	Adjective	Verb	Adverb
juvenile	Yes	Yes	No	No
preteen	Yes	Yes	No	No

As nouns, preteen is a hyponym of juvenile; that is, preteen is a word with a more specific, narrower meaning than juvenile:

juvenile: a young person, not fully developed
preteen: a preadolescent boy or girl (usually between 9 and 12 years of age)

juvenile (noun)	preteen (noun)
a young person, not fully developed	a preadolescent boy or girl (usually between 9 and 12 years of age)

juvenile (adjective)	preteen (adjective)
of or relating to or characteristic of or appropriate for children or young people	of or relating to or designed for children between the ages of 9 and 12
displaying or suggesting a lack of maturity