Maha ESL’s Answer
Karma to become a teacher you need to get a degree in Education first. Then you can proceed with your Masters and PhD if you like. You can also take the CELTA or TESOL Certificates
If you would like to teach at the college level, you need at least a master's degree in the field that you are going to teach. If you want to teach biology, then you would need a degree in some field of biology. Some small schools hire instructors who only have a bachelor's degree, but prefer at least a master's degree. If you want to be a full professor who teaches multiple courses and conducts research in a given field, then a PhD will be required. In the US science departments actually pay you to go to graduate school if you are willing to be a teaching assistant to a professor in your field.
Really, you can go as far as you want. It all depends upon what is important to you, if you want to teach a given age group and make a difference there for your whole career, you can be highly successful with a bachelor's, but if you want greater opportunity to move up from teaching to administration, then higher levels of education are required.
I hope this helps, take your time and think about what you are truly interested in, and remember that you can go back to school as you age and your interests mature. It is more difficult, but certainly doable.
Best of luck!
You can actually go up to a PhD in Education in the US. It really depends on what you want to do in Education how far you would really need to go. My brother has a masters degree in Education, which he used for his 20-years as a high school History and Government classes. He got his masters degree in Education Administration and now is an assistant principal at a high school. I would think that a PhD would most benefit you if you want to teach in college, especially teaching graduate school students.
I have a BA in English as Foreign Language, I'm finishing my MA in Spanish, I'm certified to teach both English and Spanish, and I'll get a PhD eventually. I've done short diplomas and specializations, and I have different types of certifications. So as long as you are willing to learn more, as an educator you can get to postdoctoral studies.