Hi. I am 75 yrs old and was diagnosed 3 yrs ago. Had some of the life issues you describe. I found a lot of help from the Totally ADD website. Maybe the judgement free introduction to ADHD. Or the laughter as comedian Rick Green owned up to his struggles in a humorous way. (ADD Stole my Car Keys). Or realizing that my life failures had a rational explanation. But mostly some of those videos have information about lifestyle changes that use our ADHD to accomplish life. Didn’t start medication until 6 mo ago. It has helped. But not as much as some of the other changes.
Best advice I can give is to learn all you can. This site has a lot of links and recommendations. And check out the podcast by Mickey Wright and Pete Kinder called Taking Control.
Good luck and welcome to our world.