I would nix “She still trained me.”
I’d agree, doesn’t really make sense in that context, does it? At that rate, the beginning of Luke’s next sentence needs to go too. I think it is a good concept, but we should just leave as is.
JEDIT: As much as the final lesson would be nice to include, I think the scene is more personal without it. And Luke’s 3 lessons were why the Jedi needed to end. He went back on that, no need for a lesson three or final lesson. And who knows, Luke may show up in the Rey movie as a force ghost to depart more wisdom, so it likely won’t be the final lesson in canon.