I am knitting a chemo hat for a friend of my aunt's but I don't know what size to knit. There are 3 sizes on the pattern, small (21 inches), medium (22 inches) and large (23 inches). I started knitting a medium but it won't fit all the way around my circular needle and I can't find one with a shorter cable(I'm currently using 21" size 13). Are there any other solutions I can use? Should I try knitting a large? Cut the cable on my circular needle and make it shorter? Please help.