Hi principia! Welcome to PC.

Now... I'm assuming you're referring to an undergraduate degree, right?

You CAN take courses in all of those three areas, and see what you're most drawn to and what you do the best in.

I'm not a science-minded individual, but I know my sister had trouble choosing between chemistry, physics and biology... I think she eventually chose bio-chem, but that's after taking courses in all of the different areas!

It doesn't mean you've failed and it isn't unusual to change your major during the course of your degree. I did! I also changed minors.

I'm a psychology student myself, and I'm graduating in November. I'll tell you this about psychology: It's a lot of memorization, and if you go to a larger school, then it's a lot of multiple choice exams, and very little else until you've reached an upper year.

Perhaps examining what you want to do after you've graduated??

What do you think about for a an area for your career? What do you want to be doing?

Talking to an academic advisor will also really help because they might have tests that help you to determine where you areas of interest lie.