I would recommend dividing the load equally for all the reasons mentioned above, plus this one.
This is your first year of university and while it may seem advisable to have a lighter first semester so you can adjust, having one that's too different from next semester poses serious problems (and a difference of one course can be quite a difference).
This is because, while you're adjusting to university, you might as well adjust to it and run at full steam, instead of breaking in gently and then worrying when you run into difficulties later. Having a full course load in first semester forces you to adjust to the new demands, pressures, expectations and lifestyle changes that university will bring about. It also means that you'll be more accustomed to this sort of thinking, and this way of organization when you enter 2nd semester. You will hopefully do excellently in 2nd semester, even better than 1st, given that the confusion, the apprehension and the nerves are eliminated and you're able to withstand the daily grind better.
(Plus, if you're the sort of person who needs a longer vacation to recharge or you may have plans for the summer, then it may be better to save the opportunity. (Also, if you have your courses done now, you can look at getting ahead and not catching up during the summer by doing some 2nd year courses.
))