Baby shower...Help!

Who is responsible for planning the baby shower? Family? Friends? Both? Is the expectant mother the one who picks who plans it or does someone volunteer? My friend is almost 14 weeks, and I just found out I'm about 5 weeks, and she told me she wants me and Another mutual friend to plan the shower. And I'm like uhhhhh 😳. I'm not very good at putting events together like that, and I'm sure the mutual friend isn't going to be of a big help bc she's a little on the lazy side, so everything would most likely get stuck on me and i don't have time to be stressed out about that nor do I have the money to put towards her shower when I have to be getting ready for my own...which I think me and SO will plan our own bc we want it casual...like a cookout/shower. What do I do? Idk how to tell her no without seeming selfish and making her mad. Any advice would be appreciated!!! Thank you!!