I'd say, your answer is very vague. In fact, you are raising some questions. Anyway, let me try to answer these for you.
Firstly, age isn't so relevant in this case. Secondly, not everyone needs to be vaccinated for rabies. It is administered post-exposure only. So if you haven't been exposed to a rabid dog recently, you don't need to be vaccinated.
Next, bitten by a dog who "probably" had rabies is very different than the dog who is a confirmed rabid. Any vet can confirm whether a dog is a rabid or not. It's fatal for that dog also.
Finally, you won't die of rabies because of your "probable" exposure to it some 3 decades back. Rabies is a fatal neurological disease and if someone gets it, it turns fatal quite sooner ..in matter of weeks as compared to years. So don't get worried for an incident that happened in a distant past.
Hope this helps. Thank you!
RE: What are Microwaves?