Hi Bibi,
Welcome to the forum. An 18" long snake in good condition can easily go for a month at room temperature without eating, so don't worry about too much for now. People with new snakes often have the same experience as you're having. Make sure the snake feels secure by giving it a good hiding spot.
Next time, try offering the worms in a small bowl with wet sides, so the worm can't escape too easily. Also, move the leaves away from the bowl. Then back off about 10 or 15' and see what happens. Some snakes get "stage fright" when they're just settling in, so it may not eat in front of you. If you're curious, you could remove the paper towels and leaves. They will also slow down their defecation rate when they're not eating, and there won't be a brown part (the actual feces).
Eventually, you'll want to move away from a worm-only diet, since they lack bones/much calcium. I know all the talk about parasites can be intimidating, but the fact is that this world is full of things that aren't good for us. There are even roundworms (nematodes) in earthworms (annelids). I'd just freeze any fish that you're planning to offer for at least three days. Then thaw them out under warm water, and feed away. Just make sure you're not feeding goldfish or other thiaminase-containing fish (
http://www.thamnophis.com/caresheets...?title=Thiamin,). Cheers,
Rick