Hi Martin, I'm from Argentina. And I'm a climber for 10 years.
My advice is take courses, climb with friends, and improve your skill before to go to an important expedition. A guide is not an instructor.
I've never been in an 8000m peak, but I climb a lot in los andes, an I think you have to be a very good climber to be there. A good guide is not enough.
You have the pefect age to start a good climbing carrera. You have time to learn all you need to climb a 8000 by your self, without a guide.
Good luck... Nacho.