I'm 13 and I crack my jaw but it doesnt hurt
I think so. I do it a lot, it hurts majorly right now. It's unhealthy though, your jaw could lock into place and you'd have to get surgery, or it could break..
Yes, totally normal. A little gentle manipulation of it may help reduce the cracking.
My jaws usually cracks when I eat and I am only 10 so I'd say yes