In ANH, Obi-Wan told Luke that he was "too old for this" when Leia pleaded for him to aid the Rebellion and bring the Death Star plans to Bail Organa in ALderaan.
Obi-Wan always planned to train Luke to become a Jedi. There's in-universe evidence that age does not necessarily impede on one's skill with the Force nor lightsaber.
Is Obi-Wan really too old to do this? Or did he lie just to lure Luke into becoming his Padawan? Or is Obi-Wan actually speaking the truth from a certain point of view?