Hope this is in the right place 
Will I be disadvantaged undertaking a commerce degree having literally no exposure to it? I've done no VCE subjects that are commerce related (which I now regret).
I don't think so, plenty of people who go into commerce didn't do any business/commerce types subjects in VCE and still do fine in the degree.
Also in a lot of first year subjects at uni they tend to cover some highschool content in the beginning to make sure that everyone has the same baseline knowledge.
Hope this helps
