Long stay visa for 18 year old

Is there any special classification for my 17 year old daughter who was born in China but is now a US citizen? I (her mom) live in China on a Z and she currently has a S1 as my dependent. When she turns 18 she cannot get S1 anymore (so odd that parents can but not children above 18!) but she is still my dependent and lives at home. Does her status as a native born Chinese give her any other options? THanks