A paediatrician uses percentiles as a way to evaluate whether your child's height or length is fine for his/her age. Most mothers think that what matters is the actual height of the child or the actual percentile of the child. They think that this is what will determine how tall the child is going to be when he/she grows up.
However, that's not true because the height of a child when they are only six to twelve months old does not have any bearing on their future height. So, don't be concerned if your child is not as high as your friend's child.
The important thing to consider while measuring or evaluating the height of your child is how the percentile changes over time. This is what your paediatrician is concerned about. For example, a child may start out in the 50th percentile for height, weight, and head circumference. The problem occurs when he/she moves on to the 90th percentile for head circumference but not for the other two factors. This is what the paediatrician is looking for and this is what you should be concerned about since it may indicate a growth problem.
So, don't brag about the growth percentile of the child. It doesn't mean anything. Instead, pay close attention to the changes that may occur in the height, weight, and head circumference percentile.