there is a tafe course you can do at holesglen in moorabbbin, it will teach you the basics and also give you a bit of work experience with a car audio company to just get your foot in the door. i did this course and i got a job at one of melbournes car audio specialist instal stores. the car couse helped me get the job there. At first i loved the job the audio, cars, wiring, alarms, boxes, fiberglass and the rest of it. but if like the others say, *if you dont love it you wont survive*, i did love it but didnt see it as my carrer path saw it as more of a hobby, and didnt like the shit cars to work on the hours and so on and so on . otherwise it is generally a good industry, but make sure you leave it if its not something you want to do for a living, nothing worse then being stuck in a job you dont want to do for life.
Ring the tafe and see if you can get into the car audio course, its only 6 months and it will be one of your best chances of getting into the industry.
GOOD LUCK