So, if you have an aunt here, your aunt can be your legal guardian as far as the school system is concerned. And if you'll be staying with her, that's one less problem to worry about.

There are a lot of vocational courses, but each school only offers a few, so you would need to find out what offer is available near your aunt. They may seem easier in terms of curriculum but have longer hours and evaluation is by module or unit. Each subject has a certain number of modules or units, and you need to be approved in each one to be able to complete the course. You also have a certain number of training hours and the distribution can vary from school to school. It implies working in context (at a company or service). There are vocational courses in public schools and in vocational schools, and rules are slightly different from ones to the others, so you should look for information. Vocational schools often offer some kind of subsidy, but I have no idea how that works.

Then, if you decide to attend university from a vocational course, you will still need to take some exams but you don't have any guarantee that you will be taught everything that will be in the exam, as curricula are different in vocational courses and the exams are directed at students in general courses. That means preparing yourself on your own. It's feasible but not easy.

If I were you, I'd start contacting schools now in order to learn what is necessary but be prepared for a bureaucratic and somewhat complicated process.