Question if you read "Evolution's Darling" by Westerfield

In the end, when “Memory” was telling the story of the founding of heaven, he goes back to the time that Darling first ahieves sentience. How does this fit in? He wasn’t considered the first machine to go sentient was he and thus creating an AI heaven in the pocketverse? Also wasn’t heaven really the state of mind of having no memory rather than the ringworld the 4 artificials ended up on? Any ideas?