Admissions to some second year engineering programs depend on how many courses you take and what kind of gpa you get. That's why its not a good idea to fail/drop anything in first year engineering. Even the 2 electives count and make a big difference in your admissions, to lets say civil.
In first year engineering you will have 37 units (12 courses in total, 6 each semester). Let's take an example:
Person A:
drops a course(3 units), and gets 6.5 in first year, so in that case,
34 units x 6.5 = 221 points
Person B:
Takes a full course load and does not drop/fail anything,so..
37 units x 6.5 = 240.5 points
What i am trying to say is, even if the cut off for civil this year is 6.5, if you don't have a full course (along with the 6.5), then you wont get into civil. So in that case, you have to work extra hard to get more points.
You are in grade 12, the best advise i can give you is to get as high as you can this year and get the golden ticket..i mean the free choice
Free choice is given to people who have a high average in grade 12, this is just to encourage students to work hard in gr 12. A free choice will get you into almost any 2nd year engineering program, so you don't have to worry about getting a high average in first year eng. You can also drop courses and still make it into the program of your choice. Unfortunately, failing anything, even if it's one course will take away that free choice.
Free choice does not include, management, biomedical and something else(i think chem&bio). As for what average you should have to get the free choice, i am not exactly sure, but its for sure above 90%.
In conclusion, work as hard as you can this year, get the free choice & live happily ever after!
Good luck