When do I apply and do I have a chance for Uni in Ontario, CA?

[Foremost]

Hi everyone,  

I am currently studying in Year 12 (Grade 11) and I'm wondering when do I apply. I visited many different Canadian unis website but all I can see is dates and deadline. Do I apply during my senior year or after my graduation? Because I see IB general requirement for a score to be eligible to apply, but wouldn't that be finalized after my graduation? Another concern that I have is that if I have to use my predicted score to apply this post-2019, I wouldn't get accepted since I'm going to be honest, my first term score is horrible: Mathematics SL 3, Computer Science HL 4, English A SL 4, Business Management HL 6, French AB 4, Music HL 5, Overall 26. But I believe that I can get my grades up since my first term grades have been a reminder of how much I have to work for IB and my grades have improved after term 2's mock exams. But is it too late now?

My desired university is McMaster and some other Ontario unis such as Brock and Guelph. And I want to major in Computer Science.

Also, this next question goes to everyone who major or majored in computer science in Canada. I have seen the IB general requirement for McMaster and it includes "Two of Sciences: Biology, Chemistry or Physics". But since I have decided a long time ago that I want to study computer science, I chose CS for group 4(Experimental and sciences). Does this mean I will not be eligible to apply? 

I am kind of in a dark and don't know how Canadian universities admission works since I would be the first (hopefully) to go study abroad in my gigantic family tree. I'm in a British international school that has quite a low reputation for alumni who went to a decent Canadian university. So literally I have no one to consult. 

Thank you very much 😊 

[kw0573]

In Ontario, you apply through https://www.ouac.on.ca/. You can either apply with your predicted grades in mid Y2, or with your final, but the latter often mean a gap year. For comp sci, Waterloo and Queen's are also very good. You should contact McMaster with your course options and see if you need to take additional courses to fulfill their requirements.