Complex sentence: Davidson first tried his hand at stand-up comedy at age 16 in a Staten Island bowling alley, where a group of friends, knowing of his comedy aspirations, dared him to take to the stage; he did so only after smoking marijuana.
Split into simpler sentences: Davidson first tried his hand at stand-up comedy at age 16, when he and a group of friends were in a Staten Island bowling alley. His friends, knowing of his comedy aspirations, dared him to take to the stage, which he did after smoking marijuana.