Iain Armitage, Annie Potts, Montana Jordan, Emily Osment and the cast of 'Young Sheldon' chat with ET about the series finale, airing May 16 on CBS. Iain reacts to meeting the original Sheldon Cooper, Jim Parsons, and says he was surprised at how similar they are. Plus, Emily and Montana discuss their upcoming spinoff series, 'Georgie & Mandy's First Marriage,' and the cast shares their hopes for 'Young Sheldon's legacy.