Law and AS are two very different subjects - can I assume you do not know what you really want to do?
Join the club. It takes people years to figure out. What I can tell you, is dont go after a career purely for the money. Go after a career that is closest to the way you think, and closest to the things you are interested in.
I would probably go as far as to recommend that you take a generic BCom first year in which you do Ecos 1, Maths 1, Law 1 and Stats 1. Maybe even add Management 1 or Philosophy 1 to that, if you can cope with 5 subjects. That will let you experience the subjects first hand, and you can then decide which route you want to go.
Sadly, you dont cover much stats at all in Matric, so I would think it would be difficult to decide whether it is something you are interested in. And you probably have little exposure to finance, too.
What I've realized over the years is that, personality and interests are actually more important in your career choices than your intelligence - much more important than you might think. Think about it - you are smart enough that you would be accepted into everything from Art to Statistics and everything in between. But what interests you? Do people interest you? Does debating interest you? Does business interest you? Does engineering and logical problems interest you?
If your career choice is aligned with the way you think and your personality, you will do well. If you choose something that is not aligned with the way you think and your personality, no matter your intelligence, it will always be an uphill struggle for you.
If you have no personality, Accounting is for you!