Just going to comment - I have not gotten anywhere close to physics in my computer science degree.
-- Start reply to Rui's quote
Given I have completed a related degree (more than half of my subjects came from the CS course plan at my uni), i'd say the only time you would see physics in depth is during game development units. In a general sense physics is present
in parts elsewhere but it really depends on the design of the course and what the unis want you to get out of the degree itself.
** off the top of my head-- End reply to Rui's quote
-- General Advice
I personally think specialist would be good for you rather than physics - CS has a very high mathematical requirement and imo the more you do before hand the better as it lays the framework for success early. You're right, you'll barely find physics as a pre-req in any CS course. The main requirement here is mathematics and this usually involves a prereq of methods or higher.
In terms of taking specialist itself - difficulty is subjective and just because one finds it extremely easy/hard, doesn't mean you will. See my comment below but I reckon you should consult somebody who is able to provide you with targeted personal advice before you take it on!
I would advise that you seek course maps etc. of CS degrees for unis you are interested in going to - a quick google search will assist with this. There tends to be advice on ATAR Notes from all areas which are often not fact checked or essentially opinion from those that have never been in your situation... so consulting formal documents along with professional advice will give you the best possible outcome.
Cheers, good luck! Looking forward to seeing another Computing student on here soon.
-- End General Advice