if the year 12 subjects have a pre-requisite of a pass in the year 11 subject, then no, she won't be able to proceed.

most subjects (well, when i did it) carried through from year 11 to year 12 (so unit 1-4 of same subject) and if you didn't pass units 1 and 2 you couldn't do 3 and 4

i know my bro ended up repeating year 11 cos he couldn't do his year 12 subjects after slacking off