If Op truly suffers from anxiety (right now she is self diagnosing perhaps correctly but still self diagnosing), Op needs to get a diagnosis in order to get help from the school. Then Op should take the accommodation to school and and request a 504. Op also has the option of having mom request an initial evaluation for an IEP if she thinks one is needed.
She is not going to get anything simply based on her saying that she has anxiety. No diagnosis, not help (including extended time on tests/assignments).