I usually make jokes about others (I'm an introvert) but I do make them about myself too. Actually I'm not sure if they are jokes, I just like pointing out funny quirks or observations I've made of others. Especially when nobody else has noticed them!
I find it kinda hard to make a joke about myself because it feels like I'm bringing too much of myself into the outer world - maybe it's just how I make jokes, I always relate them to personality for some reason. Not necessarily MBTI, but I often point out aspects of somebody's personality in a humorous way. "Harry is so gullible he'd believe the world is flat if we told him!" That kinda thing.
I think I'd make a lot more jokes about myself if I weren't so determined not to appear arrogant/self-important. xD