Hey,
I am doing the HSC now, with French Continuers, studied through the Open High School. I have found, from personal experience, and talking to others in my class, that it doesn't really matter how motivated you are to do the subject, it really depends on your location and how your school assists you.
I live in Newcastle, and, being so far away from Sydney (I mean that it wasn't simply a matter of me changing suburbs to get to Randwick), that I was at a disadvantage to Sydney school students. I found that students living in Sydney were presented with more opportunities to attend the school for one-on-one lessons with their teachers, whereas I was invited to the class lesson once or twice a term, with everyone else. I, for one reason or another, was unable to attend a couple of these lessons, but, as I had a good teacher, who I talked to on the phone weekly (you arrange a set time with them), sent me what was done at these lessons, and I went down to the school three times, on my own, and had a one-on-one lesson with my teacher.
That's location, now I'll explain the school part of it.
It is a requirement that your school gives you access at school to a phone, CD/Cassette player, DVD player, a place to do the work and supervised timetabled lessons. If all of this is given to you, and you have a supervising teacher who knows/will help you with the language, then you are fine, and will do well. Unfortunately, my school, and quite a few others, made you arrange everything yourself; ie. timetable your own lessons and complete the set amount of work in that time, arrange your own classroom or area in the library, arrange access to a phone/CD/Cassette player/DVD player. Also, apparently a lot of the students, myself included, didn't have a supervising teacher. On paper, we did, but all they did was take work that had been sent back to us out of the envelope and laid it out, or sent away work we had done, (which you had to package.)
Last year, there were 150 students in my class. This year, there is 63. That shows you how difficult the course is, especially a language course, when you don't have the proper resources available to you. And, also, on average, your marks will drop, if you don't have these resources at your disposal.
I am not trying to scare you off doing the course, and I wish you the best of luck, but I think you need to know what can happen.
Best of luck to you.