Why law?

I have secured a meeting with a barrister but am worried that if he asks me exactly why I want to pursue a career in law I won’t know what to say? Please help!

I am 16 and I am currently studying English Literature, History, French, Politics & Critical Thinking at college. I got 6 A*s, 4 Bs and a C at GCSE and am an extremely determined and hard working young girl who above all, wants to pursue a career in law. I have managed to secure a meeting with a barrister next week so that I can talk to him about the different aspects of law and the different steps I should take to give myself the best opportunities possible. However, I am worried that he will ask me exactly why I want to pursue a career in law, and unfortunately I have no idea how to answer that question! It is something I have been interested in since I was very young and I have decided I definitely want to become a Lawyer. But what should I say to him if he asks me that question, I would like to get a clear answer in my head now as I am aware I will be asked it at University interviews in the future. Please help!!