faylowell, I have a similar story to yours. I was diagnosed less than two years ago, in my forties. I was also well-behaved in school and got good grades. My PNP says I have the inattentive type of ADHD, which is more common in girls, and doesn't have the hyperactivity that can push teachers to seek an intervention for the misbehaving child. As I have gotten older, it has gotten worse, getting to the point where it has overwhelmed my ability to cope effectively with it, as I had done for many years. I do take medication for my symptoms, and that has been helpful. I also have borderline hypertension--see my response in Callista's thread here on blood pressure. I take BP medication and it has not been incompatible with ADHD medication.

Good luck. You are not alone!