She doesn't answer Elsa's question, and though Elsa doesn't push, she's... cautious. They finish the tour with Elsa showing Anna the nursery, and asking if she's thought anymore about moving.
Anna asks when would be a good time.
It's a lot easier to justify moving in when she takes emotion out of it, Anna later thinks. Her lease is up. Wesel-dick is putting up rent. Elsa's place is actually closer to both the hospital and uni.
But the knowledge that Elsa wants her to move in, she knows, is the real reason.