Am I thinking too lofty?

So I've finally graduated from high school, and am now going to U of T for mathematics in the fall. Once I'm finished my degree, I'll maybe get a masters. Once I'm done that, I want to do something that'll help people. And I want to do it on a global scale, like working with researchers to create new medical procedures, or helping to solve the economic problems of countries.



Am I thinking too realistically? I'm afraid that I am. I bet that a lot of people once thought the same way in university, but didn't really have the time to achieve much. :(