am I able to do extension subject?

[sushi7]

hey guys,
as I am year11 and i'm finishing 2 unit 3&4 subjects this year, I am forced to pick up another one next yr.
so I'm thinking of applying for psychology extension in Melbourne uni.
I'm currently doing eal,chemistry,psychology,religion,methods 3&4,chinese fl 3&4.
for methods and chinese, i think im doing pretty well cuz im getting As/A+s. and im pretty sure if nothing else happens, i would be able to get a pretty decent study score for those two.
but Im getting average Cs in chem and English, average Bs in psychology and religion.
however, my teacher says he cannot sign the approval form for me cuz I did not meet prerequisites.
I know the program is for students who are doing exceptionally well, but would I have a chance to try at least?