That's a great question Marla, but a difficult one!
I think it's very hard to figure out what we should do with our lives. Some people (the minority of people) figure out very early what it is they want to do, and stick with it. For most other people, they search, try things out, change their minds, and hopefully find something eventually.
Here's are a few things I've found to be helpful in trying to figure things out for myself:
- what am I good at? I like being able to do things well, so I want the thing that I spend a lot of my time doing to actually produce good results
- what are the things I enjoy? This could be more concrete things--like watching movies, or things that are more abstract, like--organizing your friends to do things. It's been really important for me to try to figure why it is that I enjoy something--do I enjoy it because I get praise from other people, or do I enjoy it because I just like the activity itself?
- what I can imagine spending all my time doing? here i'm talking about your environment. I could sit in front of a computer all day, reading, writing, analyzing things, working mostly by myself. Some of my friends could never do that--they want to be in different environments, e.g., talking to people, working with their hands. Think about what you could actually see yourself doing for extended periods of time.
- what is important to me? For me, it's important that I am financially secure. It's also important that the work I do has positive impact (whether on a few other people, my community, or a broader group). For other people I know, it's important that they have a lot of money--they want to be able to buy designer clothing, eat at fancy restaurants regularly, fly first class (notice that this is different from being financially secure).
I keep coming back to these questions. In other words, as I try new things, I try to answer these questions for myself. I notice that some of my answers change over time, but that helps me figure out what it is I want to do. I totally agree with Gary that you don't have to figure out everything right now.
However, it was always important to me to be able to have different options so that I could change my mind, and what enabled me to have those different options was to work hard in school and work to improve the things I was not good at. I worked hard in high school (on my grades and extracurricular activities) so I could get into a great college. I worked hard in college so I could get a good job. I worked hard on things I was not naturally good at, so I could keep my options open. For example, English is my second language--my writing wasn't very good, so I worked to make it better by practicing writing and reading a lot. I had trouble speaking, especially in front of groups, so I joined debate in high school to get more practice and to get better.
It's totally okay to change your mind, but think about the questions I wrote above, and as Gary suggests, explore different things so you can better answer those questions.