What I think you're trying to do is move the servo to either 0 or 180 degrees, depending on the light level. Above a certain level one way, below that the other way. Right?
Well, it is not possible that the servomotor will move at the same time as the photoresistor is receiving light?, I mean, as the led is approaching the photoresistor, the servomotor moves simultaneously. It is because I am creating a robotic hand, and I will place five different LEDs with their respective photoresistors on a glove in each finger, and I want to copy the movement of my hand to represent it with a robotic hand with servomotors to copy my movements