I see "high school teacher" as a realistic job. Even if it is somebody's dream, it's not as shoot-for-the-stars difficult as--say--winning the Palme D'Or for your film, or
being the poet laureate of the US.
I think the "average" sense of these goals is relative to what I've already done. Publishing short fiction is something I've already done. Doing it more seems pretty basic.
And I have the current credentials to teach creative writing courses, so again, I don't sense it's too far down the road.
As for why high schoolers? They're fun. They're smart. You get to make a difference at a very important moment in a kid's life.
Not to say that other moments aren't as fundamental, but a high school experience can make or break a child's willingness to pursue higher education
or, if college is something a student doesn't want or need, to be the kind of person who has a desire to always be learning.
I almost didn't go to college at all. My parents didn't support it, and no teacher ever asked me if I wanted to or gave advice on how to prepare for college.
And so it was practically luck that I went (via community college). But I did so well! My academic performance was tremendously better than it was in high school.
I went from C average to straight A's. And now I've had all these experiences that I'm incredibly grateful to have had,
and I want to support students so they can feel more at ease about what they want to do. And I want students to find something they're passionate about,
even if it's something in a subject they don't give a shit about.
I could probably go on, and this explanation would only get more disorganized, but yeah--I have a lot of feelings about teaching.