What conlusions can the reader draw concerning Beowulf's mental and physical condition prior to the battle with the dragon

Beowulf was old by then. There are hints as to his demise against such a foe. Beowulf is also tired from a life time of battles.

Beowulf is not the man he was fifty years prior, but he was prideful. His pride sustained him in making preparations. He focused on his many conquests, and he moved forward.