I'm not going to help my friend with a commitment that she signed up for. I didn't want to do it, so I never signed up for it.
Why would you not assist her? What is going on?
I'm really busy right now and it would take up too much of my time to help her.
I know how busy you are, but we have to help our friends when they need our help. Even though you're busy and you don't like the activity she's asking you to do, you should help her. Friends help each other out even when it's unpleasant to do so.
I think you're giving me stupid advice right now.
I'm sorry, but I'm just saying friendship is really precious. Being there for her when you're busy and don't like her activity really shows how much you care, and she would think of you highly for thinking of her and fitting her into your schedule!