It is difficult to address your question without knowing much about your background. Usually an MA TESOL is a course for experienced TESOL professionals or for people who already have an understanding of the subject but wish to further their knowledge. Is this your case?

MA programmes are designed for students who plan to teach in the UK and the USA, or who plan to do research on the teaching, learning or assessment of English as a second or foreign language. In the US you would need an MA to meet the licensing requirements for teaching in any public school. Many private schools also list it as one of their requirements for employment.

To enroll in a MA TESOL program you will normally need a first degree or equivalent and two years experience of teaching English as a second or foreign language. If your first language is not English, you will also be asked to provide evidence of your competence in English.

Hope this helps.