Acutally your first oil change should wait over the 3,000 miles due to that they put additives in the factory to lube all internals properly and you might be flushing them out too early. The wrench is part of the Mercedes-Benz FSS system which is adaptive to your driving style and conditions, it can vary for everyone. The wrench will start appearing reminding you of upcoming service with the mileage left for that service showing next to the wrench. When the wrench shows up with a reading of about 300 miles that means that in 300 miles service A will be needed. I got my first service at 8,800 miles.

Its up to you however if you want to change the engine oil every 3,000 miles. The resetting instructions are clearly detailed in your manual. I know of people changing their oil every 3,000 miles and not resetting the FSS system until the system informs service is due and then at that point they just get another one done and have the dealer reset it for them that way they are changing it every 3,000 miles. Remember that the FSS system was invented for that very purpose to extract the most life out of your oil. Remember only use Mobil 1.

The fact that your car only has 1,050 miles and already requires service A is that the FSS system also monitors the time the car has sat without use. So if your car has sat for a long time at a dealer prior to you purchasing it the system will also calculate that oil life sitting in your oil pan and maybe that's why your car needs service A so soon.