[emoji33] She sounds like she might possibly live vicariously through her DD. I know it would really bother me if I saw this around our gym. I know our coaches or our gym wouldn't tolerate this kind of behavior. We have strict rules where my DDs go. I don't post much but usually only browse. But...
Sibling rivalry is very tough. Consider sitting down with her and asking what she is thinking feeling having more one to ones with her. That May go a long ways. She is hitting that age where she is trying to find her way.