Rebecca Sugar confirmed that Stevonnie's age is a combination of those of Steven and Connie. As of Reunited, Steven is 14 years and 8 months old, and Connie is 13 years and 5 months old. Couldn't you then list Stevonnie's age as 28 years 1 month old as of Reunited? And I suppose 26 years 9 months before that? Does that mean while Stevonnie ages twice as fast as a normal human, she'll also live twice as long?