It was shown that He-who-must-not-be-named used his pet snake's venom when he was reborn. Nagini was one of the 7 Horcruxes and he needed her venom to strengthen him because of the piece of his soul resting inside her. Hence, due to Nagini's venom, he loses his nose and gains his horrifying snakelike face.
Youth can join Scouts BSA if they have completed the fifth grade and are at least 10 years old, OR have earned the Arrow of Light Award and are at least 10 years old, OR are age 11 but have not reached age 18.
As far as the law, under California state law there are no age limits on the carrying of knives, folders or fixed-blades.