It comes on based on a calculation the engine computer makes about how
many times the engine has been started, how long it was driven and what
temperature it reached. Plus a couple other items.

Unless you're doing some incredibly heavy duty driving,  you oughta get
a lot more than 2500 miles before the oil light comes on.  On newer
trucks like your 5-8000 miles is a more usual mileage between changes
(as determined by the on board computer)