I stand 68 cm from my dresser mirror, inspecting my scalp. How far is the image of my scalp located from my scalp?
That's pretty far away to see anything interesting about your scalp. But the calculation is pretty easy.
Your image in a flat mirror appears to be twice the distance between you and the mirror. The image will be a little more than a meter away. (I'll let you do the math.) That's about like looking at the back head of the person seated in the row in front of you at a theater.
This question is designed to make you think about what you see in a mirror. You might imagine that you had a 68 cm ruler which you held up to measure the distance between your eye and the mirror. You would observe the ruler and an image of the ruler between yourself and the image in the mirror.