Teensy 3.0 I2C LCD screen. NOW WITH BUTTON!

So after playing with the screen I'd now like to make it only display something for a short time. I'd also like it to be dynamic updating instead of just showing the message while it's on.

So I hooked up a switch to pin 7 like so:

Then I wrote the sketch below.

 #include <Wire.h>   
 #include <LiquidCrystal_I2C.h>  
 // Set the LCD address to 0x27 for a 16 chars and 2 line display  
 LiquidCrystal_I2C lcd(0x27, 16, 2);  
 int count; //Used to keep display alive while we are reading information  
 void setup()  
 {  
     pinMode(7, INPUT_PULLUP); //Set pin 7 to INPUT_PULLUP, this uses the inbuilt resistor on the pin  
      // initialize the LCD  
      lcd.begin();  
     lcd.clear();  
     lcd.noBacklight();  
     count = 0; //Initialise the variable  
 }  
 void loop()  
 {   
   //Check to see if we have pushed a button   
   if (digitalRead(7) == HIGH ) {  
    // If the count if > 100 reset the counter and clear the screen  
    if (count >100){  
    lcd.clear();  
    lcd.noBacklight(); //Turn off the light  
    count =0;  
   }  
   else{  
    //If the count is not yet at 100 then display the current count  
    lcd.clear();  
    lcd.home();  
    lcd.print("Counting");  
    lcd.setCursor(0, 1); //Set to the second row  
    lcd.print(count);  
   }  
  } else {  
   //The button has been pressed  
   lcd.home();//Send to home  
   lcd.backlight(); //Turn the light on       
   lcd.print("Hello World"); //Print a basic message    
   count = 1; //Let the count begin  
  }  
  //If we have started counting then keep counting  
  if (count >0){   
   count++;  
  }   
  // Wait a short time, then we check again  
  delay(200);  
 }  

BOOM!

Does the job for now, next I need to read something from USB and have that the thing being displayed.