One cycle does not a problem make!
That's my way of saying don't let one weird cycle throw you off your game plan. O is so transitory. I've O'd as early as CD6, and as late as CD17, even though every cycle before, between and after was CD13-14 O dates. So many things can screw up your O like illness, a new exercise routine, stress, etc. Yeah, we are said to be due an anov cycle at least once a year just as a matter of course. The positive OPKs are odd though . And you're absolutely, 100% sure that they are 100% positive (not the slightest doubt that the line is almost but not quite as dark?)?
I was going to ask about the possibility that you were pg since you are correct. An OPK could indicate you are pg. But you beat me to that. And of course, you're that magical age of 35. Who knows what happens to us after that!! I'm almost 39 so I've heard all the naysayers on that score!
So, I say keep temping (can you give us a link to your chart by the way) and see what happens. I don't know if it will cause a problem. Some say your egg will start to deteriorate since it took so long to get out, and that that doesn't make for a good pg but there are plenty of us out there who got pg on some of these 'old' eggs, and have healthy babies to show for it. That would have to be your call. But Good Luck!! Different can be a good thing. may this different cycle mean a BFP for you!