To become a middle school ESL teacher, what classes should i take in college, and how long would it take me to graduate?

Just get an English degree and a single subject teaching credential. You can do it in three years if you hustle, but most likely four. By that time, however, ESL will probably be built into every teaching credential anyway, because of all the illegal aliens who come here for free education. Are you sure you want to be a teacher? It really sucks. I've been doing it for 13 years in southern California and the conditions just keep getting worse and worse.

It depends on the state you will be teaching in and certifications requirements. In Texas they recommend classes like history of the English language, and ESL class, linguistics and study of foreign cultures for example. Each university sets its own criteria. However, in Texas if you have a teaching certificate and can pass the state exam without the coursework, you can be certified in ESL without the recommended courses. I took 2 of the courses and passed the exam without the other 2.

you do not need to take an English degree. This is not essential for ESL as you will be dealing with grammar and not the history of literature. However, you do need to take a teaching course TEFL CELTA or a pedagogical course somewhere. how to teach is the most important factor.

Go to the education department, bilingual education. You can earn a BCLAD in California.