PLEASE NOTE: we are not lawyers and this answer should not be contrued as being legal advice! In adition, the answer below is according to NY State law. The law may vary in other states. Radicalreference editor

Part 1, juvenile arrest record: According to the Corporate Counsel of New York (212-442-6160), a juvenile is a person UNDER the age of 16 (See also Criminal Code S 510.15). Also, according to the Corporate Counsel, a juvenile's record is expunged (essentially destroyed) at the age of 18. However, according to Family Court Act S 354.1, it is also possible for a juvenile "offender" to petition the court to have the records expunged.

Part 2, affinity groups: According to New York State Criminal Code S 510.15, juveniles (under the age of 16) must be held in youth facilities.

Commitment of principal under sixteen. 1. When a principal who is under the age of sixteen is committed to the custody of the sheriff the court must direct that the principal be taken to and lodged in a place certified by the state division for youth
as a juvenile detention facility for the reception of children. Where such a direction is made the sheriff shall deliver the principal in accordance therewith and such person shall although lodged and cared for in a juvenile detention facility continue to be deemed to be in the custody of the sheriff. No principal under the age of sixteen to whom the provisions of this section may apply shall be detained in any
prison, jail, lockup, or other place used for adults convicted of a crime or under arrest and charged with the commission of a crime without the approval of the state division for youth in the case of each principal and the statement of its reasons therefor. The sheriff shall not be liable for any acts done to or by such principal resulting from negligence in the detention of and care for such principal, when the
principal is not in the actual custody of the sheriff.