If I were you I would get a really good accountant--esp in NY.
"Non-profits" are generally required to keep really detailed records beyond that required for a "for profit" business.
You could get many if not most of the same benefits by self-incorporating without some of the headaches.
Then again I really don't know the tax structure for NY.
If most years the donations by your students don't cover your expenses for classes then I'm not sure that going NPO is really going to help you much--you will still be coming up short in terms of out of pocket payments.
Maybe I'm misunderstanding???
I did battle with ignorance today.......and ignorance won.