Oh, no . . . I don't think you've gone down the hearing aid road prematurely at all. I had my ReSound Dot220 about 6 months before I had CK, and I still use that same aid every day since. I've had it almost 3 years.
Of course, I didn't know at the time I got the aid that I had the AN, or I might have asked the same questions you're asking. Trouble is, no one can say whether your hearing will deteriorate quickly, or maybe it won't change at all. My hearing has changed very, very little in 3 years, even post-CK. So getting a hearing aid is a gamble. Factors in making your decision may include how much your insurance pays, whether you can afford an aid that has lots of room for adjustment as your hearing changes, location of your tumor, etc. My hearing loss ranges from mild to severe, depending on the frequency. The hearing aid DOES help, but I wish it could do better. I DO highly recommend the ReSound products, as I'm very active and I haven't managed to destroy this thing yet. It's been accidentally swimming/showering several times and still works!