First, running Perl on Windows is a PITA. Just to compile a module with a XS component is a major hassle. Everything works so much better on Linux, so your first priority should be to get the school to switch to Linux ( or a variant). That way you get free, easy to use C and C++ compilers, then Perl just naturally falls into place.

Well, that would disqualify Perl right from the start. I'd say any language that would require you to switch OS would be totally unsuitable for teaching. It's like saying "I'd like to learn how to cook" and getting a response "Sure. Cooking on electric is such a PITA, so your first priority should be to get a gas stove."