Yes, you would be over-qualified. Note that in order to make a living coaching middle school or high school track and field you’ll need to teach or at least find a job that you can work as your primary source of income. Middle and high school coaches receive coaching supplements, not salaries. This is true in all of the examples I’m aware of though such jobs may exist. (?)
Coaching supplements can vary widely from very poor to decent money (a percentage of a teacher’s salary-5%-10%- as an example) but it hardly constitutes a salary. Coaching high school American football, on the other hand, in some states can be very well paid to just coach (and possibly not teach at that or any other school) but in track and field that is not likely to happen.
By background check, yes I’m referring to seeing if you have a criminal record.