Welcome Maz, You should be fine removing the decals from a year old car (colour will be fine). The easiest way to removal any vinyl is a steamer, if you don't have a steamer lots of hot water. This softens the glue more consistently than a heat gun/hair dryer and should leave no residue. Just try and get the car clean as possible first and have a clay bar to hand once you've removed the vinyl, for any grime around the edges.