> Get checked and officially diagnosed.

That can be a surprisingly difficult process.

For example the NHS isn't entirely sure how to diagnose ADHD in adults. My GP didn't even know it was possible, and had to go and make phone calls to find out where the nearest specialist was. Unfortunately if your answer to "Did you get bad grades at school?" is "Not really" then hard luck, as they want evidence of underachievement as a kid to confirm the diagnosis. And there really is no way to complain your above average grades were underachievement without sounding like a dick.

It wasn't until I was in the final stage of my degree that somebody noticed that I had problems, and luckily the University helped me get a private diagnosis for some of my issues.