An if statement isn't checking if a variable has increased in amount or not

I am programming in AS3 on flash develop. I am using a program called flashpunk that adds in multiple presets for classes that i can use to make it easier to program. I have an if statement that is supposed to add a new graphic when a variable equals 1. If the user presses one on their keyboard then that variable does increase by 1. But when the variable increases by 1 and the if statement is supposed to check if it is one it doesn't add a new graphic like it's supposed too. I do have the if statement and the variable in different classes and i am not sure if i can do that, here is the code. The if statement that doesn't work is the one that is supposed to add a new background1.

Chapter

package 
{
    import net.flashpunk.Entity;
    import net.flashpunk.World;
    import net.flashpunk.utils.Input;
    import net.flashpunk.utils.Key;

    public class Chapter extends World
    {
        public var mainmenu:MainMenu;

        public var background1:Background1;

        public function Chapter() 
        {
            mainmenu = new MainMenu();

            add(mainmenu);

            background1 = new Background1();

            if(mainmenu.YesNo == 1)
            {
                add(background1);
            }

        }


    }

}

MainMenu

package 
{
    import flash.events.TimerEvent;
    import flash.utils.Timer;
    import net.flashpunk.Entity;
    import net.flashpunk.graphics.Image;
    import net.flashpunk.utils.Input;
    import net.flashpunk.utils.Key;
    import net.flashpunk.FP;


    public class MainMenu extends Entity
    {
        [Embed(source = "net/MainScreen.png")]
        private const SPRITE1:Class;

        public var YesNo:int = 0

        private var sprite1:Image = new Image(SPRITE1);

        public function MainMenu() 
        {
            graphic = sprite1;
            sprite1.centerOrigin();

            x = 200
            y = 150

            layer = 150

        }


        override public function update():void
        {
            if (Input.pressed(Key.DIGIT_1))
            {
                YesNo = YesNo + 1;

            }
            trace(YesNo);
        }


    }

}