major change?

Over the past couple of weeks I have been thinking a lot about what I really want to do with my career. As of now I am a declared interior design major... but now I am not so sure. A couple days ago I was talking to Danielle, and she was telling me how excited she was about nursing...which got me thinking. When I was younger that is what I wanted to be, but kind of grew out of it. Now I am considering it again! I'm so nervous though because I know the classes are going to be really hard. So I don't know what to do...any suggestions?