Hi TexasGirl:
I think it's best to consider your goal:
-Continue working in education and/or working in a non-profit involved in education and/or doing research.
As a former middle and high school teacher now in non-profit and will be pursuing grad school this fall, I know what you might be going through. The big question for me was: How do I get the experience and the opportunity to transition? I would explore opportunities to allow you to work in different sectors of education. Seek out professional opportunities like non-academic fellowships or even volunteering opportunities. Maybe you can help conduct focus groups or edit reports.
Is a masters from NYU worth getting into so much debt and not being able to save for the next 6 years or so before I begin doctoral study?
It all depends on what you want. Why NYU? Do you want more of a practitioner-based degree or a research-based degree? Your answer to this will vary on how you will transition into a doctoral program. If you engage in enough professional research work you can even apply to doctoral programs without the master's degree. You might even luck out an find yourself in a PhD program with full-funding. Long story short, explore and really soul search!
Is 35 too old to go for a doctorate? Should I just wait and apply to a doctoral program next year?
I say no. The more prepared you are for a doctoral program, the easier it will be to apply to, go through and finish. Another question is, what do you want a PhD for? There are professional not-PhD doctoral programs toward degrees like an EdD.