between 13.3 and 14.8 is pretty normal. It will be higher just after starting as the alternator is topping the battery back up.
The diode pack and regulator will adjust based on load requirements. So it will be higher charging and when electrical items are turned on. You will find it gradually lowering over a 15 minute period as the top up of the battery completes.
If its 12.5 immediately after starting then you may have issues with a dead battery in the near future. But if the car has been running for a bit and you have nothing turned on, that is perfectly fine.