Yes a common age for young officers to enter the Navy was about 12 or 13 as volunteers or captain s servants followed by promotion to midshipman by 13 or 14 see Nelson for example Some successful officers joined when older but that meant 17 or so see Cochrane In Patrick O Brian s books there were several instances of young midshipmen getting wounded and having amputations It was not uncommon for a severe limb wound to be amputated especially if infection set in