Am I slower? I really don't know. That's the honest answer.
I mean, I've got almost a dozen years of Strava data that conclusively says: maybe?
How do I really know? And how much do I really care?
Facts are facts: My bikes have all changed for-the-better by several iterations in the aforementioned dozen-year time-period; fires, floods, and new construction have radically changed our local trails, in some cases for-the-better; technology, frame- and tire-design have all changed my riding style and abilities for-the-better a thousand-fold; and sure, inevitably, so has my body changed (tho not always for-the-better) as well as the way that I sometimes feel before, during, and after I ride (again, not always for-the-better)... So, which of these variables am I looking at when trying to determine if I'm slowing down?