Can I ceramic coat a car that has just been repainted?

Freshly repainted panels usually need time to cure fully before they are polished or coated, because solvents in the paint continue to evaporate after the job is finished. Coating too early can interfere with that process. The required waiting time depends on the paint system and drying method used, so ask the body shop when the paint can be polished and sealed, and follow their guidance rather than a general rule.