yes you do need physics 1L03 before 1B03 if you didn't need take grade 12 physics, also this is just a personal suggestion- but I would consider switching out one or 2 of your courses for electives.
Personally I did 5 science courses in my first term and found it to be quite draining, also you can take 1st year courses in upper year.
Some elective suggestions
1. Choose a subject you are really fascinated by, if you gives you a chance to learn something new
OR
2. Opt for an elective with a "lighter" workload such as Econ 1B03 or 1BB3, one of the 1st year Anthro courses or geo 1HA3 or 1HB3
Also choosing an elective that has a term paper or 2 could be beneficial- most 1st year science courses are basically midterms and labs, and when you get second year life sci there are courses where you will be required to write essays/ research reports
just my two cents, but I really hope you choose Mac! It's an amazing school