Hello MuddyPaws!
Welcome
How often will you be having lab work to monitor if your levels are going down? It is best to have lab work done before any reductions in dose. As Ann said, the aza takes up to a couple of months to really kick in so waiting til that point to decrease pred is a good idea. Definitely ask about budesonide as there are far fewer side effects with it. My hep had mentioned that it is becoming more common to start AIH patients off with that and also for treating flares. The good thing is you don't have significant damage (well I'm assuming as you didn't state the severity of it from your biopsy only that it was inconclusive for AIH).
AIH is very treatable. It is different for everyone and some folks have more side effects to deal with. AIH patients, when under control and responding well to treatment, can expect the same life expectency as anyone else.
Also, see if you can get a referral to a hepatologist.