How can I know if I qualify as a highly qualified teacher?
You must meet some basic requirements to qualify as a highly qualified teacher, with additional requirements depending of if you are a elementary or secondary school teacher and whether you're new to the teaching profession.
And how do I know if I'm teaching at a low-income school? I worked in an Indian reservation school.
All elementary and secondary schools operated by the Bureau of Indian Education BIE or on Indian reservations by Indian tribal groups qualify as low-income schools.