I got it when I was 17 in NJ. Not sure how far into NY you live, if your close to the border or not. Maybe you can take it there and then apply for NY reciprocity. There(NJ) you only need to be 16 to take the class, but if you get it before 18 it really isnt beneficial because you can't take on patient care until 18. Admissions for medical/other health fields like to see that, but if you just get it a month before you apply to med school its worthless. What they like to see is that you have some SOLID time doing EMS so you can say I want to go into medicine because of my experience here. Or my experiences here made me realize I want to pursue a career in medicine. I hate it when people get it junior year of college because then its so obvious the only reason they went through with it was just to write it on a resume.
So I would def recommend taking it soon, maybe pay your bills in college working nights or weekends on the ambulance or volly. You will be surprised because it will most likely reaffirm your decision to go into medicine or wont if you truly work in the field for a few years. You will see and work with higher health professions to aspire to: ie EMT-P, PA, MD/DO, Respitory Therapy, PT/OT, Pharmacy, etc.....