I was wondering if there are any retired military or veterans on AC because I had some questions. Does anyone know if Tri-care health insurance is accepted there? Can you still use the retirement program even if you are under 45?

I'm not military, but used to be a practitioner for Tri-Care. They aren't here. You may be able to hand file claims in the states if you have prior authorization and international benefits are in your policy. But there is no recognition of any US insurance as far as we know. With regard to your other question, others will know.

You have to be 45 or older. Check this website out.
Belize Retirement Program

Medical care iss very problematic. Most retirees go to Miami or Houston for anything serious. don't count on belize to assist in getting you payment. But a provisional policy for Belize..both availble in the US/Inernational insurance pricey of Belizean produts..noy the best policy and worthle outside Belize.

I find the doctors in San Pedro and Belize City to be very good. Not sure where Timmy is, but our experience has been excellent. BUPA insurance covers us here and abroad. The providers do not bill the insurance company for you, but BUPA assists in processing paperwork and you do get reimbursed if you are due money.
An office visit is affordable - from $30-50 Bz, and surgeries are also reasonable.
Think of Belize like a small town - if you need specialized care you may need to travel to a hospital that specializes in that area. Another popular location for medical care is Medrida, Mexico. There are excellent facilities there for more sophisticated treatments such as chemo, heart surgery etc.