I did exactly the same thing. I was interested in forensics and asked my teacher last year if we could do Forensics but we ended up doing Shipwrecks. Now that I've looked at the Forensics topic, it doesn't look as interesting as I expected, and now I'm not 100% sure if I want to do forensics since there aren't many career opportunities available in Australia. I don't think it'll help that much. If it does then you could always borrow books from the library and look over the forensics topic.
Shipwrecks is a pretty interesting topic. Better than what I had expected.
If you are interested in Forensics, you're better off choosing courses in Uni such as Medical Science or even Advance Science since there are many branches of science available including Forensics as opposed to just forensics which basically locks you in only that particular career. However, UTS has some forensics courses available.
Anyway, good luck.