How to make a grandma's bonnet/nightcap?

[Tensmumym]

My dd is playing a grandmother in a play and needs a nightcap/bonnet, I think a bit like this. I'm not particularly good at sewing, apart from darning socks and sewing on buttons. Am I being overly ambitious to think I could make this?? Any tips as to how I could do this? Thanks.

pattisoriginals-pattisplace.blogspot.com/2010/12/tutorial-mop-cap.html

This looks like a good tutorial. I like the way that by making it double sided you don't need to hem it and can make a channel for putting the elastic in.
Good luck.

Thanks very much Trumpton. I think I will be brave and give it a go!