The big choices are in your hands. Your faculty adviser is just that, an adviser. Most often, you tell your adviser what you are interested in/what you want to do, and they tell you how you might make it happen. Of course, they are prone to offer suggestions about which courses to take and the like, but when it comes down to what you want to study, only you can answer that. The most friction that you might encounter is when you start to talk about advanced work which (depending on the discipline, your plan, your course history, etc.) might require you to take certain courses to be considered a [insert discipline] student. For instance, I’m a junior and I want to do advanced work in philosophy next year, so I’ll need to take a course next term offered by the philosophy faculty (one of which happens to be my adviser) to accomplish this.
In general, faculty advisers are at their best when they are forcing us to think more critically about what we are studying. In that sense, they are helping us to know (and articulate) better what we already love.
Finally, you can switch advisers if you are so inclined (I was). You just need to find another faculty member who is willing to take you on as an advisee.
Hope this helps.