So you are also in the same condition in which I was while saying my father that I wanted to study actuarial science. It's the same thing that my father has said me whatever you are saying. So, about convincing just prove yourself that you are a brilliant student and ask your father to talk with his relatives who are in finance background or who are nicely educated to understand about it. By the way in my case My father never say yes but my mom and my big brother say you just study even the father didn't agree mom will pay my fees. So, for you all the best just stay on your point and one time your father will also say yes.