What do I do if I am not sure about what career I want to pursue?

Ask your school if they know of any career fairs in your area. They are good because you not only get to learn about different jobs, but you also get to meet people who have them.

You can also look into different clubs that may specialize in areas (like engineering clubs or teaching clubs). You might even be able to find a shadowing program, where you get to go to work with someone and see what they do. Hopefully you school guidance counselor would be able to point you in the right direction in finding these opportunities.

Also, don't put too much pressure on yourself to know what you want to do. Most students enter college undeclared. I had no idea what I wanted to do when I graduated high school. I stumbled into my job while I was in the Army.