Maybe the OP could be a little more specific as to what their interests/career ambitions/future study plans are? Are you interested in running your own business? The preparation of financial statements and some general accounting/sales type theory or are you more interested in the economy as a whole? This may be hard to answer, in fact, at the end of year 10 I couldn't really say that i knew what the economy even was!
If your unsure, economics probably is a little more diverse and challenging then BS. It is the study of choice essentially, how economic agents (such as individuals/firms or gov.) allocate their limited resources in order to maximise their economic wellbeing. It encumbers everything and is really a foundational study of understanding what happens in this world from politics to marketing and financal markets. Things you will look at are microeconomics ie structure of certain types of markets, nature of demand and supply, price elasticites and general theoretical models and then also macroeconomics concentrating on certain issues like unemployment, the causes and effects of economic growth, exchange rates and international trade along with inflation and the various types of economic policy tools employed by the gov and our central bank.
I did eco and absolutely loved it, finding it a huge advantage and now study it at university. Having said that, i also study accounting and if i would of had done BS in high school it may have given me a slight edge at the beginning of uni.
up to u anyway!