Billie Eilish, 17, has a lot to learn when it comes to Saturday Night Live,and host Woody Harrelson and the rest of the SNL cast show her the ropes in their new promo. Billie Eilish Is The 'New Kid' (And Almost Gets Bullied) In 'SNL' PromoEilish will serve as the musical guest for the Woody Harrelson-hosted episode on SaturdayBy James Dinh