How to convince my parents to let me become what I want?

I have to choose what college I want to go to and my parents won't accept other college than the one that they have chosen for me.They say that if I'll go to what college I want,I won't be able to find a job.But I don't think that it is true.I have good marks, that's why my parents want me to study medicine,architecture or something related to physics and chemistry.When I was 7 I wanted to be an architect and they've agreed.At 12, I've wanted to become a doctor and they have agreed.Now I want to study finance or business administration and they don't agree.They say that I won't be able to find a job and if I don't graduate from a very good university, the degree in finance is useless.They also say that a degree in medicine from a cheap university is good, but a degree in finance from a cheap university isn't.My parents can not pay for a famous university and they want me to go to a cheap one.I've found some universities that are very well ranked(not in top 5 ), but in top 10 where I could study business-related studies but they still don't agree.It's not that I don't like their options,but I really think that finance is what I truly like.How can I convince my parents to let me study finance?