Answer: underage

AnswerCrossword Clue
UNDERAGE

Not old enough

UNDERAGE

Too young

UNDERAGE

Not yet legal

UNDERAGE
Not yet 18
UNDERAGE
Minor
UNDERAGEDeficiency
UNDERAGE15, say
UNDERAGEToo young.
UNDERAGEImmature.
UNDERAGELike some collegians
UNDERAGEUsing a fake ID, perhaps
UNDERAGEBounceable?
UNDERAGE20 or less, at a bar
UNDERAGEIn the minority?
UNDERAGENot 21 in some cases
UNDERAGEShortfall
UNDERAGENot yet able to vote
UNDERAGECarrying fake ID, maybe
UNDERAGENot legal, in a way