Mammals and birds have a limit to their growth but reptiles do not stop growing. Their growth rate may slow down as they get older but they continue to grow until they die. Duckbill dinosaurs are an example of a dinosaur reptile where we have examples that got to 30 feet and two to three tons.
(Book – Digging Dinosaurs – John R. Horner and James Gorman)
I didn’t know this about reptiles; it’s very interesting! (So I wonder if a reptile’s length is to any extent a reliable indicator of its age.)