I just turned 40 and I never thought I had ADHD until recently. Before I just thought my lack of attention on things was just the price of being a 10X on productivity (and I was a little arrogant because of it).
The reality was that I chose to put my time on tasks that I found interesting and engaging and when that choice was not available, I would feel anxious, stuck and totally unfocused. Still, I thought that was just normal procrastination that everybody goes through.
Some changes in my life and goals limited my time to act and required me to be more focused, but instead of getting into action I got more stuck than ever and very anxious as the deadlines got closer and got missed.
Treating my ADHD helped me change my relationships for better and widened the possibilites in my work and I would recommend to anybody in the same situation.