Age 18 - no licence - got night yard shunters job at National Carriers doing rigids, Scammel coupling and fifth wheel artics 15’ to 40’ trailers - first thing I drove was an old Ford scammel coupling unit with the fifth wheel plate attached on top and it had a 40’ box trailer with a single axle at the very rear - what a nightmare as there was a pillar every 20’ - no expanse roofs without pillars in those days 
At 19 I went to National cariers own driving school at Peterborough on a 1 week residential driving course and passed test at the end of the week in a 7.5 tonner I cycled to work and back for 3 years and drove a 7.5 before I got my first car - what - a dinky toy 
Passed HGV Class 1 in 1988, advanced car in 97, advanced lorry in 98.
Passed all my driving tests first time and without any test nerves so I am unable to say to my trainees “I know how you feel” if they have nerves or fail - but I do sympathise as best I can.
Started teaching advanced (voluntary - still is) in 98 and LGV instructing in 2005.