Let me see..."Too young" is rude?
"Too young" is disrespectful?
Webster's has it this way:
1 a : being in a rough or unfinished state : crude
b : natural, raw
c : primitive, undeveloped
d : simple, elemental
2 : lacking refinement or delicacy:
a : ignorant, unlearned
b : inelegant, uncouth
c : offensive in manner or action : discourteous
d : uncivilized, savage
e : coarse, vulgar
3 : marked by or suggestive of lack of training or skill : inexperienced
4 : robust, sturdy
5 : occurring abruptly and disconcertingly
Maybe english as a second language would help, The Duke, David, et al.