Originally Posted by
czwhat
You can get a class 3, but you are going to have to work on getting it. I have one and I am only 19. I used this service called pilot medical solutions and they made it easier to get the medical. You have to keep your sugars under control and monitor it in flight. I'm in the same boat as you I have wanted to be a airline pilot since I set first foot on an airplane and now I can't.
A type II can often manage with diet, exercise and no insulin, but a type I who requires insulin will be limited to a third class (with operational restrictions). This means you can be a private pilot, but may not work as a commercial pilot in any capacity. It is remotely possible that the rules might change on this at some point in the future, but I doubt it.
You can still go into aerospace engineering, aviation maintenance, or another relevant technical field and work on airplanes all day, and fly for fun.