^ If its still in you dont take it out as it could make the bleeding alot more severe and also maybe damage something, so til the ambulance gets there you pack something around the knife to try and stop the bleeding as much as possible.
I hope thats totally correct...I learned it in first aid class a long time ago.
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My Random Thought....
Who cares about age milestones! Most of the time they either make you stressed because youre older, or put pressure on you to accomplish something before they come along, and then what happens if you DONT accomplish those things? You feel like shit...til the next age milestone comes along!