transform.childCount not working as intended

I am building my first game with unity, a simple break out game.i am intending that when the level has no children it moves to the next level.but it doesn't seem to work.in the code I put this in the update methode.

 else if (_currentLevel != null && _currentLevel.transform.childCount == 0)
                 {
                     SwitchState(State.LEVELCOMPLETED);
                 }
                 break;

which call this code

 case State.LEVELCOMPLETED:
                 Destroy(_currentBall);
                 Destroy(_currentLevel);
                 Level++;
                 PanelLevelCompleted.SetActive(true);
                 SwitchState(State.LOADLEVEL, 1.0f);
                 break;

but it doesn't even get into the first condition although in the editor i can see there's no Childrens. PS:Sorry if it's not clear if any more details are needed I will add them.