First, I do want to praise you for choosing something that you enjoy as a career path. One advantage we have when it comes to ADD/ADHD is the ability to hyperfocus on things that we enjoy.
Honestly, the summary from your post is pretty on point about the reality of someone with ADD/ADHD. Did you share your doctor those information (Elementary School, Middle/High School & work experiences)? It is perfect in my opinion.
You should expect that the neurological test might tell you exactly why you have concentration problems. Having an answer is better than always wondering/being stressed about what could be the problem. In my case, after I learned about my ADD, I was finally able to move on, to get the specific help I needed and to find out actual solutions to my problems.