Odor from armpits has nothing to do with age. The odor you notice is a sign for the breakdown of the different components of transpiration, so if your daughter was very active, doing sports or in a highly heated room the odor might be an indicator that she transpired in her armpits. You can get her an dermatological tested child friendly deodorant if she would like to, just make sure that her possibly sensitive skin is fine with it to avoid rashes.
