We now know that the final scene in Avengers: Infinity War where Gamora asks her father Thanos "what did it cost" and Thanos responds with "Everything" happens in the soul world as the Russo Brothers confirmed. It also appears that Gamora is aware of what happened in the real world (outside the soul world) and that the snap killed half the universe. My question is, why did Gamora appear to Thanos as her younger self and not in her adult body?
I believe the reason Gamora appears to Thanos as her younger self is because earlier in the movie when Gamora is telling the story of Thanos taking her and killing people on her planet, she's a child. Then at the end she appears to him as a child because it's that version of herself that experienced those events.