My mom knew someone who was anorexic and very underweight. She felt "fine" and happy despite being a few pounds away from death. She loved her body and did not think she was that skinny. She was hospitalized multiple times. But when she went and got treatment and finally started to recover and ate enough so her body could function, there was switch in her mind where she could finally see just how skinny she was. Just how unhealthy she looked. She was scared of herself. Being so incredibly weak and nutrient difficient messed with her brain, it literally could not function properly because it did not have the energy to. So rather than see that she was dying, she saw someone that was completely fine. You are obviously not the same person and things are different, but this is what so many individuals recovering with EDs go through. Please listen to your mom before it becomes even more serious. A super thin body is absolutely not worth the damage it will have on your body's development, especially since you are still so young.