Polar knit skull beanie

[cmhoover1]

I got this amazing pattern and went right to work with the recommended size 9 needles and worsted weight yarn. (to fit 21" circ. head) I thought it would fit a teenager, but it was more like a toddler size! I guess I should've done a gauge swatch, but the pattern led me to believe that it was for s larger child. I'm going to try the bigger needles (10s) but maybe there's another pattern out there designed for teenagers?