Time Lapse Code

int buttonState = 0;
int buttonPin = 8;
int LEDpin = 7;
int LEDon = 0;
double reaction = 0;
int press = 0;
void setup() {
  Serial.begin(9600);
 
}

void loop() {
  press = 0;
  pinMode(buttonPin,INPUT);
  pinMode(LEDpin, OUTPUT);
  buttonState = digitalRead(buttonPin);
  digitalWrite(LEDpin, LOW);
  LEDon = millis();
 // Serial.println(millis());
 // Serial.println("millis");

 // Serial.println(buttonState);
 //Serial.println("before while");
 while(press<1){
    buttonState = digitalRead(buttonPin);
 //  Serial.println("while");
  if(buttonState==0){
 //  Serial.println("if");
   reaction = millis() - LEDon;
 //  Serial.println("reaction");
 //  Serial.print(reaction);
  Serial.print("Your reaction time was ");
  Serial.print(reaction);
  Serial.print(" milliseconds.");
  Serial.println();
 
 //  Serial.println(buttonState);
   digitalWrite(LEDpin, HIGH);
   delay(5000);
 press = 1;
   }
 
// else if(buttonState>0){
 //  digitalWrite(LEDpin, LOW);
 // Serial.println("Button is not pressed");
 }
}

Circuit (same as read button press - LED + button)