Although I didn't exactly repeat yr12 - I did repeat yr11. Failed the first attempt (too many day absent) - first yr doing yr12 May 2002 I dropped Eng and 2003 I made the decision to go back to TAFE to finish my VCE. Glad I did, might not have received a good ENTER - but at least I have options available now. If you want to repeat just go for it - I had the comments it's not worst going back to complete my VCE (but I did, and do not regret it for a second) - Also, I think most of the time age is a factor deterring ppl from final decisions, whether to repeat or not - but by the time you reach Uni I'd say w/some courses you'd actually find quite a number of students mid 20's +. Heck, my mother met a 2nd yr nursing student in her 30's.
I know TAFE offers a lot of options in Vic for students who did not do well in VCE - and depending on the Uni course after you have finished at TAFE can always go on the next yr & apply to your chosen Uni degree. Best of luck to everyone