It's very common to take first year courses in later years. Do be aware of the prerequisites for upper year courses when choosing which course to (potentially) put off a year.
It would probably be easier if you focus on getting set up to major in one of two things rather than trying to be ready for everything - it may not be possible to fully set yourself up for Computer Science, Chemistry, AND Biology, but you can probably fully do the first year requirements for two of them. That doesn't mean that you have to abandon the idea of pursuing the one you don't chose, you could start it up in your 2nd year and probably not have to take extra time for your degree (or maybe you'd need to do one summer course, etc).
If it makes you feel any better about your potential schedule, Intro Programming usually isn't too bad if you've got some programming experience
Remember that it often takes just as long to do a search or two on Google to try and find the answer to your question as it takes to type it in a post here, let alone the time waiting for a reply.
If your question is "What mark does it take to get into University X", or "What are the requirements to get into University X", it's on their website and/or
electronicinfo.ca (for Ontario schools). Particularly for Ontario schools, those ranges are a pretty good picture of what kind of mark will get you into the program, and if you're more than a couple percent higher it's practically guaranteed unless it requires a supplementary form.
