This is definitely good, but I'm not a fan of how most artists draw aged up child characters with standard cartoon child features. stubby hands, overly round faces, a lack of detail. That pic doesn't do it nearly as bad as others I've seen, but it's still apparent.
This pic is just a bit too far in the other direction but it's the best I could find.
Also that aged up Dexter is perfect dude, has that artist done any more of him?