YES! Everyone has experienced it and you are by far higher than MANY people for second week losses.
The first week is generally very high because you are losing fluids. The second week some people have less fluid to lose or are in a type of shock from starting to adjust to ketosis.
Losing 3 pounds your second week is not just great it is well above the norm for many people.
Your friend may have had a lower week 1 weigh in, she may weigh more than you to begin with, OR she may hold even more fluid than your body does and she is still releasing it.
DO NOT judge your success on this diet based on another persons performance. Men lose faster, people heavier than us lose faster, people with more allergies may lose faster, etc. There are many reasons this diet becomes a very individual process. ONLY decide your success based on your inputs and outputs.
YOU ARE DOING GREAT!!