It is not a normal part of growing up at all. When I was in high school, our football team played a team from the other side of the city (inner city type area) that was mostly Black. During the game the people from that inner city school did indeed pull out out some knives and start to use them. The game was called off. The high schools used to have rumbles against each other so maybe the knife thing was born out of a previous rumble. Who knows.