Since the OP’s school is a grade 7 to 12 school, it may be that they primarily offer 1a and 1b courses for the equivalent of high school level 1, since that is commonly what middle schools offer to 7th and 8th grade students. So a student starting a language in 9th grade could take four years to complete high school level 3 (1a, 1b, 2, 3) if there is no level 1 (instead of 1a and 1b) course offered.