I am a great believer of preventive maintenance.

Carbon is a by product of combistion. Therefore it starts to build up any time the engine running, which means the day you got the car from dealer. On GDI engines the carbon buildup is faster than PIE. Mods are done by engine manufactures to delay this process. However no modern engine is free of this carbon buildup. So it good to do decarb anytime to keep your engine running in top shape.

Your situation is a little cautious. Your car is still under warranty. You will void warranty if any 3rd party tempers with the engine. I'd suggest wait till warranty is over. Then you can decarb your engine every 50Kkm to keep it in top shape.