I'm so pleased that you are interested in teaching. It is a wonderful profession. Yes you can become a teacher in 4 years. First, think about which area you might be interested in the most - young children, middle school or high school? Is there a subject you really like more than another? Is there something you are an "expert" in?
I majored in Elementary Education and Special Education. Because I had two majors, it took me 4 1/2 years to complete. In your last year of school, you have to do an internship in a school based on your major. Because I had two majors, I completed two internships. It was worth it!
I wish you much luck and success ..... if there is an after school program in your area, volunteer to get some experience and to help you decide which path is the right one for you.