If you are pulling with your arms, you can overdraw the bow and pull it way past your ear, if you have the strength and/or a weak enough bow.
If you are pulling with your back, it is virtually impossible to overdraw the bow, because you will run into a wall where your back muscles have contracted as much as they can contract, and your drawing shoulder blade has moved as close to your spine as it can move. Your drawing arm is relaxed, and your elbow has described a J shape rather than a straight line.
So in order to avoid overdrawing your bow, you need to learn to draw with your back muscles.