To start with, where do you currently feel limited in your life? What made you seek a diagnosis?

Personally, I couldn't keep a job for years. This led me to realize I had ADHD and get diagnosed. You seem to be successfully running a company, so you might have developed the good coping skills to deal with your limitations already.

I recommend reading Taking Charge of Adult ADHD by Russell Barkley. It's a good first book for people with ADHD and can answer a lot of basic questions about medication, therapy and feelings you might have after being diagnosed.