Hii

To  become a professor in English subject a high qualification would be required. You need to go first for English (Hons) or BA English. This is the undergraduate course in english. It would be 3 year long course. 
Once you omplete the UG course, you will need to complete MA in English and MEd. These would be of 2 year duration each. 
Now you can get a job as lecturer but to be in good colleges it would be suggested that you complete your higher studies PhD in English. 
SO, first you need to earn a bachelors degree, then a masters and Doctrate of Phillosophy.
This is how you can be English Professor.

Hope this helps
Thanks!