I was your age when I made a similar decision. I can't speak to the diabetes part, but here are 10 points to consider:
1. Can you afford to be an EMT? It doesn't pay much and could be a lot less than you're used to making. Try matching revised income to expenses on paper before you have to do it for real.
2. Is your family on board? You're less likely to work regular hours in EMS than in most other professions; plus, you'll have new stressors and risks. If things aren't in good shape at home, they'll probably get worse.
3. Other than IDDM, are you healthy and fit enough for physical work?
4. Try this: List five things you don't like about your current job and five things you think will be better about EMS. Then get opinions from EMTs and paramedics about your expectations.
5. Do you like people, in general? Can you relate to unhappy strangers for 15-30 minutes, several times a day? If the answer to either is no, you'll be at a disadvantage in EMS.
6. Have you ever provided regulated services to the public in person, one on one? If not, you're looking at a big adjustment.
7. Do you have long-term plans involving finances, family, business, health, geography? How would EMS fold into those?
8. How flexible are you about sleep? Can you wake up in a hurry, be productive, go back to sleep, rinse and repeat?
9. How would you feel about taking direction from someone much younger than you?
10. Do you enjoy working closely with others, or are you more of a loner? The latter wouldn't fit as well in EMS.