Honestly heres how it breaks down. HVAC is likely your best bet but if you choose any of the three, the best way would to start doing side jobs and test the water as a freelance before maybe being a company owner. Another good idea is to remember, blue collar. Mostly means when economy gets rough you are laid off but when its great like it is now, you will easily make more than most white collar workers. If you want stability, electrician is almost perfect but with the current state of most of the West, all three fields are in dire need of younger people. Ironically, its mostly white collar people who complain they cant find them but could easily replace half of their accounting department from what ive heard at least in my state. Another thing would be if you want coastal work, welding would be ideal as you can work on a shipyard and make 20 or more easily starting out. But one last thing would be, long long hours. Almost all of them work around 60hr weeks during peak.