I would check it again once the trans gets warm, and I will assume you know that is also when the engine is running. It will usually show a bit higher.
I am no transmission mechanic, but I have a friend who is, and he has always told me it is better to have a hair too little than a hair too much oil. His explanation is that if the fill level is too high, the trans can whip the oil. If this happens, it can add air to the oil, and cause the pump to cavitate. I dont know if this is true, but I do know that cavitating a high pressure pump will eat it in no time.