Here are all kind of headboard DIY ideas from right here on Hometalk: https://www.hometalk.com/search/posts?filter=Headboard%20ideas
If you type "headboard" in the search box and hit enter you will find a number of ones that instruct you on making them. I hope you find one you like. I have chosen one for you, but there are many more for you to see, Belli. I hope this helps: https://www.hometalk.com/6484522/diy-diamond-tufted-peacock-blue-velvet-headboard
I would choose fabric over shower curtains which would be too short and too skimpy for a luxurious look.