The HJ did carry pennants similar to this in the early period Pretorian but yours is BDM as Steve mentioned: Mädelgruppe 27 BDM-Untergau 496.
This sub-forum will give you the location of the Untergau: Hitler Youth Bann number lists - Area triangle lists (you would need to upgrade your account to Full Member though)
Garry,
Did the JM wear the same sleeve insignia as the BDM mate?