From your profile I see you're not a teacher, but a student. No worries, but that adds a layer of complication to things. It should still be doable. If I were you I'd first find somewhere to dive that is easily reached after school and some means of getting everyone there. Do you already have somewhere in mind? I'd do this even before I gauged the interest of my fellow divers. Also, are you trying to get already certified local kids together to dive or to manufacture future buddies?
Your profile again mentions Mexico, Florida etc, but not Mississippi. I don't know if the river is suitable for drift dives there but I would hazard a guess not, so it's down to lakes, quarries or organizing maybe one or two trips a year to somewhere “exotic”. Is that what you had in mind?
Logistically: Does your school have a pool to practice skills in? Is there somewhere nearby to get air fills, gear rented, etc? (Something always breaks) Is there somewhere secure to put gear during school?
(Arizona, I suspect it’s a lot easier to start a club in Thailand, where you can pretty much throw a brick and hit a fabulous dive site, than in a central US public school.)
I think it’s a cool idea, but there are a lot of questions to get answered to ascertain its feasibility.