Geez, your school sounds like mine - other than a couple of Commodore 64s, the only school computers I encountered were the old TRS-80s (couple of the model 2, but mostly the Model 3/4 units that were keyboard, monitor, and disk drive(1 or 2) all in a single "box".
And yes, seemed like different computer companies had their own dialects of BASIC back then (as evidenced by the "Micro Adventures" books, where you had to enter/debug/run BASIC programs as part of following the plot of the books, they had adaptions for Apple, Commodore, Amiga, TI, etc..)