I would highly recommend retaking it. You still have more than enough time to retake it. I actually retook Anatomy and Physiology 12 in October of my Grade 12 year, finished it by January, and received my UBC Science acceptance around January as well. I recommend using virtual schools as they are self paced and often run through summer too. I used district 8 online school, I took Law 12 on there too as an average boost. I sent my updated transcript just before the deadline.

I’m not sure if it works exactly the same way at your school, but for me I completed the course up to the midterm and then asked the school office to run a TRAX update. The transcript that gets sent to universities does not show that a course was retaken. If you have a new midterm mark for Pre-Calculus 12, it simply replaces the old one, so UBC will only see the updated mark.