Turtles are cute. Even if Aang keeps expected to have them be turtle-ducks. Somehow those heads on those bodies just looks strange to him.

"Hi! Are you new here? My name is Aang."

Momo had alerted him to the presence of someone in the yard, and now the lemur was perched on his shoulder examining the newcomer. Possibly to see if she was feeding the turtles, as well as playing with them. Momo had priorities, and the woman didn't appear to be a threat.