I'd say just either ask her if she is ok and tell her (if you think so) that she can stay at your house for like sleepovers and just come over to hang out if she doesn't feel safe? Also, just reassure her and tell her that she is great the way she is and she does not need to do better. Tell her something like bronze and silver are very good and that she is amazing at the sport u do. Usually, in these situations, you should tell an adult, but then it could escalate and become a huge thing that involves many people and then at school and at whatever sport everyone will know and her parents might get mad. However, it is a good idea to tell someone, just like if you think it won't do anyting then maybe not. Talk to her about it and tell her that she can always talk to you and ask if you should tell someone. hope this helps.
tell her that she is an amazing person no matter what people say
