Hello everyone! I am looking for some help

First of all hi everyone and thanks for contributing to/providing such an informative site. Now on to my questions, I'm 22yrs old, live in the eastern suburbs of Melbourne and currently doing a uni degree in science. I've been curious about acting on and off for a couple of years now, but as yet have not really done anything. Back in school I didn't do any acting or drama classes, though I was performing in school orchestras for most of my school years and later choir as well. Now I've come to the decision that this is something that I believe I need to explore, though I'm not sure for how long yet. As I have no previous experience in acting I was curious as to where I should start. I've been looking into doing an intro to acting short course, one place I've come across, I think through this site, is the The National Theatre Drama School and I was wondering if anyone would recommend this course or if not which course they would. Next I was wondering about initially signing up with an Extras agency so I can get out there and see first hand how everything works and to have some fun. The problem is I'm not really sure who I should seek out since as I mentioned I have no experience and after spending much time on this site(before I signed up) I am somewhat cautious about just contacting any of the agents in Melbourne. So I was wondering if there was anyone out there that can recommend a good extras agency, specifically one that will look past my lack of experience and even assist me in finding my way. Well that was longer than I had originally intended. Thanks for your time and any help would be much appreciated. tinky