I was probably old for a New Grub at HMAS Leeuwin… I turned sixteen in late May, 1980. We entered New Entry Division in early October.
New Grub was a derogatory name for Junior Recruits in their first three months at the JRTE (Junior Recruit Training Establishment). Wet behind the ears. Learning the very basics.
The bastardisation hierarchy at HMAS Leeuwin began with three months as a New Grub, the next three months as a Shit and, finally, three months as a Top Shit. As a New Grub weighing under 60KG this was the bottom of the heap.