Semi-younger days? Remember this character dies at around 900 years old. So 20-30 years is nothing. The only thing that would make him age faster would be living in the swamps, but even that would be like a drop in the bucket to him. So him being young and vivacious in the PT really isn't thinking too logically. Just like when Lucas tells his actors that Chewbacca is the junior league in ROTS, when that character is over 200 years old in the OT.