Is it normal for the doctors office measurement to be off by 3 inches?

Ok so I KNOW I'm 5'8. My friend says she is 5'6 and both her and I agree I'm taller than her. I'm taller than my teacher who says she is 5'6. And I'm wayyyyyy taller than my mom who is 5'2 and my grandma who is 5'4. I have measured myself with a height chart and a tape measure. I... show more Ok so I KNOW I'm 5'8. My friend says she is 5'6 and both her and I agree I'm taller than her. I'm taller than my teacher who says she is 5'6. And I'm wayyyyyy taller than my mom who is 5'2 and my grandma who is 5'4. I have measured myself with a height chart and a tape measure. I have perfect vision, so it isn't like I'm just thinking I'm taller when I compare my height to others. I am taller than all 20 girls in my grade except 3 but I am 1 year younger than everyone due to a late birthday. I'm the tallest out of the grade below. So why the heck did the doctor measure me at just short of 5'5? My mom agrees that this measurement was wrong. At the doctors office, the nurse made me stand directly against the wall, which isn't how you stand up straight, and lean my head back so I was standing not straight at all. If I had stood up straight I think I would have been taller. I remember when I was leaving I glimpsed the wall again and noticed I was above the 5'8 mark( with sneakers). And I know height is just a stupid thing but I don't want to be an average height 13 year old girl. I want to be above average at absolutely everything. Also, this thing screwed up my weight because I weigh 140 pounds which is normal for 5'8 but fat for 5'5 so the doctors were telling me to lose weight. Even though I don't look fat. :(
5 answers 5