So you want to be an Aerospace Engineer? To begin, you must get an idea of what you need to do to prepare for a program of study in Aerospace Engineering:
High School Students - You should start focusing on your college education now! It's not too early. You will need to take as many math and English classes that are available to you at your high school. Most high schools offer Advanced Placement math and English courses and completing those courses would be best. You should take math through the highest level of calculus that is available to you. The Aerospace Engineering major requires a significant amount of math and physics background in order to understand the Aero specific courses. All Aero courses are based very much on math and physics so you must be prepared to focus your time and energy in those areas.
It is helpful, though not required, to take some sort of drafting course that includes an introduction to visualization, sketching, and drafting. A basic knowledge of hand tools shop practices, and shop safety would also be beneficial.