What am I missing?

My sister-in-law’s best friend is supposed to be throwing my SIL a baby shower. Tonight, that friend started asking me which weekend I thought we should do the shower, what kind of food I wanted to serve, and so on. I’m not throwing this shower, so WTF?

I’m confused, and I don’t want to flat out tell her I’m not throwing a shower because spending my money on buying a new house is far more important to me than blowing it on my tantrumy SIL, but I don’t know what to say to her.

And why the hell is she asking me those questions anyway if she’s the one who’s supposed to be organizing it?