Your life after school will not just be about work. You need to balance your work life, personal life and social activities. At the same time, you need to make sure you have the resources to pay for this lifestyle.
Knowing what is important to you is useful for planning your subject choices at school and for making sure you go through all the steps you need to reach your life and career goals.
Don't just think about what these things are, think and plan for how you will achieve them. For example, what do you need to do to live in your own place)