3 stone since January is great OP, well done.
I guess it depends on what your starting weight was, and what her weight is. I had a friend who was over 20 stone, and she did brilliantly and ended up losing nearly 9 stone. However in the beginning, at around the 3 stone point, it wasn't necessarily that noticeable, particularly as she was wearing mostly the same clothes at that point, which hid any loss. She was also someone who didn't ever have lots of fat around her face, so it was only at the end of the weight loss that her face started to look different.
In contrast, if your friend is say, 9 stone, and has managed to lose around a half stone, which can be possible, although it will mostly be fluid, if she has lost from around her face it may be quite noticeable.
Focus on your journey - you are doing great, and TBH I always find the people who go on and on about their diet, their wonderful weight loss and simply boring everyone about it, are usually the ones stuffing their faces with cake the next week, once the novelty has worn off.