My gauge did not match perfectly. Width-wise I was oversized, but round-wise I was way too small. It took me a minute to figure out why 5 rounds worth of the chart looked more like a skull cap than the slouchy beanie pictured on the pattern. I ended up making 7 repeats of the charted pattern, plus the decrease round.

I used 3.25 mm double pointed needles for the ribbing & 3.5 mm circular for knitting the body, until there were too few stitches, and I went back to the double pointed needles.