Well, what exactly is the admission cut off for Life Sci? It would help to know where it was originally before the "4%" increase. I can't verify that, but it might be true considering that in the engineering faculty, the next year cut offs have also increased considerably.
As well, if I recalled correctly, it's not only a question of skimming by on the cut off line, but also a question of number of applicants. If you're really worried, you're only half way through your second semester in high school, so if you fear that much, you could push yourself to maybe bump that grade average up a percent. I mean, it is doable