Yesterday I came home for lunch and Mina was having a nap, so I decided to supervise. Pretty soon, we were snoring and drooling together. She gets super hot when she sleeps, just like me.
When I woke up, I smelled her head and thought about how long babies retain that newborn milky smell. My best guess is until six months or so. It may linger a bit longer than that, or it might just be your imagination.