Jilly thinks she's figured out how life works. But when her sister, Emma, is born deaf, she realizes how much she still has to learn. The world is going to treat Jilly, who is white and hearing, differently from Emma, just as it will treat them both differently from their Black cousins. A big fantasy reader, Jilly makes a connection online with another fantasy fan, Derek, who is a Deaf, Black ASL user. She goes to Derek for help with Emma but doesn't always know the best way or time to ask for it. As she and Derek meet in person, have some really fun conversations, and become friends, Jilly makes some mistakes ... but comes to understand that it's up to her, not Derek to figure out how to do better next time-especially when she wants to be there for Derek the most. Within a world where kids like Derek and Emma aren't assured the same freedom or safety as kids like Jilly, Jilly is starting to learn all the things she doesn't know-and by doing that, she's also working to discover how to support her family and her friends. With You Don't Know Everything, Jilly P! Award-winning author Alex Gino uses their trademark humor, heart, and humanity to show readers how being open to difference can make you a better person, and how being open to change can make you change in the best possible ways.