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.