Overall, I'd focus on confirming that teaching is what you really want to do. If so, then what grade level? Elementary vs. Middle vs. High School are quite different.
You could sign up for tutoring services in High School and/or college to see how you like helping out fellow students. Check with local schools to see if they need class volunteers so you can see teacher and kids at various grade levels.
Based on which grade level you'll want to teach will help you determine the right major and classes in College.
In order to be an effective math teacher, it is imperative to have an adequate appreciation and understanding in mathematics. Hence, focusing on a major in mathematics should be considered a viable option because it also opens other doors for you in your future career paths. Another alternative is majoring in education with a minor in mathematics.
I am currently in my first year teaching high school Algebra 1. I am what they call an alternative pathway teacher in New Mexico because I did not major in Education. In college, I studied Political Science and the Arabic language. During my junior year of college, I applied for a program called Teach For America, which takes people with any Bachelors Degree and places them in an area that is experiencing a teacher shortage once they are accepted.
There are multiple ways to become a teacher. You can go the traditional route and major in education; however, if there are other things you are interested in possibly pursuing, you can always major in something other than education and do an alternative licensure program like I am doing. In May, I will have my teaching license in the state of New Mexico, and I will be finished with my first year teaching! I hope this helps.