Yesterday I soloed for the first time in a Cessna 172. Immediately after takeoff the Engine Oil Pressure annunciator light illuminated, so I had to taxi back to the FBO area immediately upon landing. The oil pressure and temperature guages were both in the green, but the annunciator stayed on.

Needless to say, I DID NOT expect this to happen on my solo flight!! My instructor said he had not seen this happen to any of his other students during their solo flights. I'm curious.. how many students experience some malfunction like this on their first solo?