After you graduate from high school, you will get your 4 years of college. You can major in practically anything in college, so that is a plus. (It's not like med school where you have to major in science.) I would recommend government or history since these involve law topics. You need to get good grades in college and good scores on your LSAT's so you can get into law school (3 years). I would strongly recommend an LSAT review course. You should do some internships while in college and law school in the field of criminal law or criminal justice. Law school teaches "book law" for the most part; internships and jobs will provide hands-on experience. Finally, you'll take the Bar exam in the state(s) where you want to practice. Good luck to you!
Criminal lawyers specialize in the defense of individuals who have been accused of committing a crime. They research cases, represent clients in court and negotiate punishments. Prospective criminal lawyers typically complete seven years of full-time study at an accredited university and law school, pass the bar exam and secure licensure before practicing law.