That would bring up the question of, what was Obi-wan doing for 19 years? Sitting watching Luke grow up. Meditating on the Force with the spirit of Qui-Gon? Or did he slip away from time to time to do things? Special favors for Organa. Helping try to save other Jedi? Running a Rebel cell until things got too hot, or Vader started to get too close? Obi-wan was thought dead by the likes of Tarkin, and Vader had not seen him since Mustifar. He'd have to go really low key, or be really lucky no one put two and two together to figure out it was Obi-wan.
Maybe a tale on how he became known as Ben Kenobi?
Maybe a tale on how he became known as Ben Kenobi?