Focus on studying to get a job that you will enjoy doing. You want to be able to wake up every morning and look forward to going to work, that is the most important thing. I would rather make 45,000 a year doing a job I truly love than make 250,000 year doing a job I hate. Most people work at least 8 hours a day, that is a really long time to be doing something you hate.
Success is waking up every morning and being able to do whatever you want, and if that thing you want to do happens to be your job, then you have made it.
If you aren't sure, just go to college and start with physics as your major. This will let you know how much you truly love it. You can always change your mind about your major and remember that you need a 4 year degree in anything to get into medical school.