I found college to be so much easier on my ADHD. I had fewer subjects to juggle, and I got more choice in what I studied. I took classes that were related to my chosen career path, so they were INTERESTING. I did have to take minimum required classes, but I tried to mix those up with classes in my major.
If teaching English is something you really want to do and gets you fired up, studying should at least be loads easier than high school. If you find yourself struggling with attention sometimes (not every part of the course will be awesome most likely) try finding a study group. Sometimes getting that interaction with other people can get you more sucked in to a topic.
Congrats and good luck