My head size(cranium) is 22.5 inches, is that too small for a man?

Supposedly that's average but then again the average human has less than 2 legs. So really you should have an above average head to be normal, right? When I look in the mirror it looks so small, I feel like a brainlet. I think it's cause of low test or poor development, but puberty is over so I missed my chance...