Year 12 can be the best year of your life. When I look at a Resume, if the applicant has not got the ability to knuckle down for a year of study at 16 17 18, I worry.
You should have some sort of passion for the subjects that you study so you are not bored. If you think of year 12 as the first step in becomming a professional pilot, I think you will do year 12.
Why would an employer choose you over someone who has completed year 12? You are not Chuck Yeager, you are one of thousands without finishing year 12 your application will be throwm away.
Write to the airlines, to pilots, tell them you need a mentor. You need someone real to guide you.
Go to your local airport, meet real people. Do not sit at home looking for answers online.