28/10/14 (6:35pm) for me, young onset as I was a youthful 49 at the time.
Slowing down a little, refusing to give in to it, trying to keep active (cycling, walking, running etc.) and started on medication, Sinemet Plus.
On a good day, I feel almost normal, on a bad ... well, less so. I think most of the problems are on the inside, hence "the darkness within", and as to the speed of progression/degeneration, I'd say with my happy-head on that I'm not much worse than I was when officially diagnosed. Like many of you, knowing means you can usually trace back your symptoms months if not years, at least 4 in my case.