Should I study economics or business administration?

Business administration.

There are two fields called "economics" and they hold opposite viewpoints. One is "Keynesian", used by bankers to justify high taxes and creating counterfeit money to finance the country. The other is "traditional" or "Austrian", used by anybody who has to deal with reality and show an actual profit. I suggest you go to mises.org and read the free materials. If that sounds like good sense to you then you can take some classes there.