Hi,
Well first have you applied to faculty of science? If so you should look at your program requirements
http://www.science.mcmaster. ca/ass...vel-i-programs
If not, I am not 100% sure but I believe you look at the undergraduate calendar (select your program which is on the left hand column)
In addition to this you should also look at what the Level 2 program requirements are and think about what major you want to go into and see if you're taking the right courses in first year to get into the program in 2nd year.
I hope this helps!
Good luck