Regular old Dino oil does eventually break down over time, even just sitting around, and the additives in it lose effectiveness.
Synthetics have a bit more stable shelf-life, but aren't immortal.
If I were you I'd get the oil changed anyway; $100 is cheap assurance to prevent my driving around and worrying about it.
Better safe than sorry, as they say.
Just go to a place that recycles the oil, so you're not causing unnecessary stress on the hippies.
