I have recently completed honours in pure maths and I can tell you, that this is a good indicator into doing mathematics at university. If you get a credit average in 1st year advanced maths, even though it is the minimum standard, it is not recommended to do advanced mathematics in 2nd year, especially in analysis and algebra, as conceptually it is quite different to anything that you have experienced.the online self assessment from http://www.maths.usyd.edu.au/u/PS/advanced.html,
is this a good indication of whether you can enrol
to Mathematics Advanced unit of study for first year?
is this reliable?
Then you get to 3rd year, and thats just beautiful, but at this stage you pretty much have to eat, breathe and live maths. 1hr/wk/subject is not enough in my opinion, you must be fluent in every subject to continue. differential calculus and linear algebra lead into integral calculus and discrete is very nice and I encourage people to take this (unless you know that you are keen in statistics early). You can always take all 3.
In reference to jobs, there are heaps, just google "maths jobs" or "math employment".