I haven't yet found the full requirements necessary before a boy could carry the Bann, Jungbann, Gefolgschaft and Fähnlein flags but I do have them for the girls so here goes and there may well be many parallels between the boys and the girls:
For Untergau and JM-Untergau the requirements for the girls were:
Minimum age: 15
Minimum service in the Hitler Youth: 3 years
Minimum height: 1.68m and of good aryan appearance
Minimum rank: Mädelscharführerin or JM-Scharführerin
For Mädelgruppe or JM-Gruppe:
Minimum age: 14
Minimum service in the Hitler Youth: 2 years
Minimum height: 1.60m and of good aryan appearance
Minimum rank: Mädelschaftsührerin or JM-Schaftsführerin
Each girl had a nominated replacement in case of illness etc.
For Untergau and JM-Untergau the requirements for the girls were:
Minimum age: 15
Minimum service in the Hitler Youth: 3 years
Minimum height: 1.68m and of good aryan appearance
Minimum rank: Mädelscharführerin or JM-Scharführerin
For Mädelgruppe or JM-Gruppe:
Minimum age: 14
Minimum service in the Hitler Youth: 2 years
Minimum height: 1.60m and of good aryan appearance
Minimum rank: Mädelschaftsührerin or JM-Schaftsführerin
Each girl had a nominated replacement in case of illness etc.