How can i become an actor?

Well i am at the age of 15 going on 16 and i have taken a very strong interest in acting, as in being on the big screens or on a television show, i have done plays when i was in elementary school to junior high school so i have somewhat a experience with a crowded audience and acting in general. I currently live in New York, but i have not done any acting in my high school yet, this year i am going to try to see if i can be in a drama club. But i have done a project in cl that had involved acting out and my clmates told me i did an ace job at my role. I have read on some autobiography's of other actors (i.e. Will Smith, Leonardo Dicaprio, Samuel Jackson, and more). i wanted to know how to get started as in what to major in, in college as well as any other beginner steps, i really would like to be successful and i believe i can achieve this goal if i have the right steps... can someone please give me advice or pointers and tips, please and thank you.