Try checking out a local university or college to find out more about classes to take for Geology. You can look at the Major requirements, class description and coursework requirements. For all science careers, you will need to take a variety of classes (if you are going to a 4-year university/ state school) including biology, chemistry, physics, some math classes, and other general education classes.
Here's a website to get you started looking at some the course requirements for Geology majors. This is for California, and I'm not sure what state you live in, but you can get an idea of what kinds of classes you will need for the major. Look under "Majors," then by "Area of Study," then, "Geology."http://www2.assist.org/exploring-majors/Welcome.do
Here are some different kinds of careers in the field of Geology:http://www.personal.kent.edu/~cschweit/Stark/whygeologymajor.htmhttp://www.onetonline.org/find/quick?s=geologist
Hope that helps!