At the age of 17 I just showed up with a hammer and tool belt at a local HVAC shop and told them I now work there! The owner told me I had a lot Ba**'s and laughed at me and so did everyone else. As I turned to walk out he said "hold up kid" I was just giving you crap, sit down in my office and will talk. He explained that I would eat crow for a year first and hate it, then I will see what your made of. That lasted about 90 days and I was made a duct installer from plenums to boots, later I was allowed to cut them in floor top register side. My mentor was a crusty 70 yr old biscuit who could not even read! He took manuals and acted the part but when inspectors looked at his work they were astonished, I think he had been a pipe fitter and such before HVAC. He never carried a tape measure and I back tracked him and got caught, I almost never worked with him again, he accused me of thinking he was lying! The guy was always dead on-go figure? In short 5 yrs of eating crow and I became a service tech, Now 35 yrs later I am at highly respected senior service tech adviser and still do calls every day (if you don't you fade away)! *I realize it is all different these days*. Good Luck and hope you get the next Crusty Biscuit like I had!