I'd go ahead and take the ASTB, seeing as how the math doesn't really exceed Algebra II, which I would assume you would have taken by 10th or 11th grade.
As far as ASTB retakes go: 30 day wait for second test (as mentioned above) and 90 day wait (from 2nd test) for the 3rd and final testing.
As far as ASTB retakes go: 30 day wait for second test (as mentioned above) and 90 day wait (from 2nd test) for the 3rd and final testing.