a bit further -
A barrister is a specialised lawyer who only does advocacy - court arguing. To be a barrister, you'll need a law degree/completed the LPAB Diploma.
At this stage, you'll be a solicitor.
To be a barrister, you need to take an extra series of exams - the bar exam, see here for general information:
The New South Wales Bar Association Home Page.
You don't need to come first all the time. In fact, what I think is most important to the practice of law is hard work and a sense of humility. The fact you are participating in competitions and giving it all a go is promising indeed.