11 years old is the typical average, we've seen them as young as 4 and more senior than 11. Diabetes is mostly a later stage condition of acromegaly, so he could have been acro before being diabetic. The vast majority of kitties get their acromegaly diagnosis as a result of the diabetes, but not all. In hind sight, Neko had at least one symptom about 6 months before getting her diabetes diagnosis.
Fat Pants was diagnosed at 12 years old, first with diabetes then a few months later with acromegaly. He also showed acro symptoms before the diabetes diagnoses. His bloodwork 6 months before diagnoses looked good but I questioned his vet about the jaw changes and his occasional "creaky " walking at that same appointment. She thought the jaw was from sticking his tongue out due to arthritis pain but looking back they were clear signs of acromegaly. He always had super loud breathing and big ears and paws.