Our potluck has three desserts and no main dish. Do I need to change the cake I already promised?

I'd bought the ingredients for a lemon cake when the final potluck messages arrived: brownies, fruit tart and my cake. The only other contribution was a bag of crisps.

The host messaged me privately: "You're the most confident cook. Could you do something savoury instead?" I could, but I'd promised the cake early, and the ingredients cost part of my food money for the weekend. The brownies were claimed after my message; the tart came from someone who said they don't cook.

I don't want to arrive at a dinner made entirely of dessert. I also don't want being able to cook to mean my contribution is always the one that changes. There are six of us, and nobody has said what the host is providing. Should I agree to switch, offer to help arrange a shared main, or ask the whole group to revisit the plan? My mixing bowl is still empty, so there is time.