So I have a birthday cake I have to decorate tonight (It's already baked). The mom is coming to pick it up tomorrow and the little boy's birthday party is on Sunday. I felt fine yesterday but when I woke up this morning my throat was hurting. And now I'm starting to feel worse. The worst headache, my body is achey, throat still hurts. Should I tell the mom that I can't make it because I'm sick? She asked me to make this cake a few months ago. I would hate to tell her at the last minute that I can't do it, but at the same time I don't really want to. Should I just make it anyway? I'm new at this so I don't know what I should do.

I'd call your customer right away and tell her that you think you're coming down with something. Based on your body ache comment you might have the flu, and if I was the customer and you let me know I'd be happy to have you cancel on me!

If you know another cake decorator who can finish the cake, call and ask them. Otherwise, as @costumeczar said, call your customer and tell her you are sick.