Logie
According to Edward M Spiers' "The Late Victorian Army", the War Office experimented with the "recruiting age band" and set a recruiting age of nineteen to twenty five years from 1881 to 1883; when it was restored to eighteen to twenty five years. Of course, the difficulty for the Medical Officer undertaking a recruit's examination was whether the stated age corresponded with what he had in front of him. Doubtless, the official line was blurred on numerous occasions. Every enlistment paper I have seen has provision for a signature and usually the handwriting was good to excellent.
Standards of literacy amongst soldiers of the Victorian era appear to be the subject of some dispute. By 1889, the Army annual returns described just 1.9% of other ranks as illiterate; with 85.4% rated as possessing a "superior education". Those percentages were disputed by the Director of Military Education based on the soldiers who possessed a 4th class Army Education Certificate.
Regards
IL.