First, just to be mean, I gotta tell you that you press the clutch pedal down to DISengage the clutch. With that out of the way, it does sound like tranny bearings in your case. Biggest thing is the 2-second delay...

If it were the throw-out bearing, it would go away instantly. Most times, it goes away when you simply put a little pressure on the clutch pedal, but you don't even have to disengage the clutch.

When you're in neutral, with the clutch engaged (pedal UP), the input shaft of the tranny IS spinning. So there's a small handful of bearings that are spinning. If you suddenly disengage the clutch (press down the pedal), it takes a second or 2 for that stuff to coast to a stop. If you open the hood & listen while your sister pushes in the clutch pedal, you can probably hear it slowing down as it stops.