Bicep cirference...?

I'm 17 and about 135 pounds. I have one huge bicep because of bowling. Long story short, in an argument about whether or not bowling is a sport on a myspace group and my bicep came in to it and he said it looks scrawny and only has definition because I'm skinny... So he asked the cirference so I measured it and it's about 13.5 inches. He's acting like this is scrawny, is it?