I've had Addison's since age 8, now 19.
I am a tiny bit worried about energy and stuff when having to work long hours and night shifts etc. But I think it could be managed, maybe have to increase meds though to compensate for extra energy used. At one point I was working 25 hours while studying full time (and trying to go out and have a social life as it was my first year of uni) and I managed completely fine with energy, was just a little overwhelmed at having no free time to myself. I say go for it! I would hate for Addison's to hold any of us back from something as big as a life changing career, and I don't think we should let it. Just be prepared to work hard, and be ready to put in time to look after yourself (developing a good sleep pattern, taking extra meds at the first sign of illness, good nutrition, exercise, social balance). Best of luck