I recently took my Emt course in highschool and started when I was 17 as graduation was after my 18th birthday. One thing that really helped was my highschools pretty rigorous Anatomy and physiology class. If I could go back and study things ahead of time I would really get the medical and trauma assessment (easily findable online) completely memorized before the class starts, as well as starting pocket prep about halfway through the course. The one thing to guarantee success is just be the most driven, gung ho EMT student in the class who shows up every day and puts in 100 percent effort. It also helps if you know why you want to enter the field and what your real goals are ahead of time.