Which is a better path?

I'm a new college student and I want to teach English as a Second Language. Tambien es q yo hablo espanol y estudio espanol como mi primer sujeto en la universidad. I study Spanish as my undergrad major. I figure getting a bachelors in Spanish will demonstrate my proficiency in the "second" language and then follow up with a masters in ESL/TESOL. Is this a good idea, or do I need a degree in English first?