@Skilodracus Sorry, but I do get what she is trying to say. By reading the entirety of the chapter you'll understand too.
Basically The mc managed to replicate the choreography perfectly by the end. However, she is the center, everyone will be dancing the same song with the same choreography.
The MC can't just dance perfectly, she needs to set the pace of the choreography and not just follow it, that's what it means to be the center.
What the woman was trying to tell her was for her to have more personality in her dancing. "Don't just copy the choreography, make it your own." Pretty much this.
This is a case of where there is no "parts to fix", this is the part where the MC has to develop on her own.