hello all, I feel the need to chime in a bit and give some insight. For those of you who are only 18/19 years old, it's great that you already know what direction you want to lead your life into. So on this note, props to you!
However, here's some down-side that you DEFINITELY NEED to think about as a 18/19-year-old:
It seems to me as some of you are planning to take the GMAT in a few months. Now keep in mind that your GMAT score is valid for only 5 years. Assuming that you're going to college, and you're coming out of college successfully at the age of 21/22, you'd still need to work at least a few years before you should be thinking about business school, let alone Harvard Business School. If you're planning to work 3 years post college, which is a typical length of work experience post-college for most top 20 business schools, your GMAT score won't be valid anymore when you apply to business school. In this case, you'd have to prepare AGAIN for a good score for these top schools.
My suggestion is to focus on your college work for now (and you can always start studying bits by bits starting now) and really think about taking the GMAT in your junior/senior year of college. This way you'll have time to gather that work experience post-college and still have a valid GMAT score.
That's my 2-cent...