Pekkie,
You have all the time in the world to decide who you wanna be when you grow up. At 19 I was a completely different person to who I am today. I'm 32 now. If I've learnt anything over the years it's that there will be plenty of opportunities to make life choices. Sometimes it seems, too many!
Don't believe the bullshit 'they' tell you about the hsc, uni and having a career. This is just one way of achieving 'success'. There are plenty of other ways, some of them more conventional than others.
What's really important is that you take the time to get to know yourself first. You know, work out what's important to you and what's not,what interests you, what turns you on, whether you have the discipline it takes to get through uni or whether you would be happier growing tomatoes on a farm in the country.
You might acquire this knowledge by journeying to the four corners of the world, by living in other countries and experiencing other cultures or by immersing yourself in the life of your community right here at home.
At 19 you are just beginning an amazing journey. You are beginning to get to know the person that you are and the person that you can be.
Uni and all the rest of it will wait if it has to. If you feel you need to take time to travel and explore now.... then do it. Choosing what to study will be so much easier when you have had the chance to experience life outside the world you live in now.
If however you feel ready to do it now, then jump in and give it all you've got.
I chose the work, then travel, then study, then work route. It worked for me.
I've travelled, lived, loved, studied, made mistakes, done good deeds, been bad, broken hearts, had my heart broken, changed careers...... Over the years I've grown into myself. I really like who I am and where I'm at these days. The life I dream of now is very different to the one I dreamed of when I was 19. But those life changing decsions still have to be made every now and then
I guess ultimately, as Chaos said, it's as simple as doing what is in your heart. Working out what that is is the hard part!
It's taken me a long time to get to where I am now. Sometimes I've cursed myself for doing it the way I have but in the end I'm glad I've done it the way I did. I've got no-one else to blame but myself, I've made every single one of those life changing decisions. And that's strangely satisfying.
Good luck Pekkie.