Most children do not understand why questions at that age. Developmentally, it is the last "wh" (what, where, who, etc.) question to be comprehended and used. Don't worry! She'll learn it when she's ready, most likely without being "taught".<br><br>
I'm not sure what you mean by her not understanding why she does things, though. That's kind of a general statement...what are you referring to? I am sure she has reasons behind the things she does and is probably aware of some of her reasons some of the time. She is at an age where she does not have much control over her impulses, though. So she may do things (even sometimes things she may "know" not to do) because she can't control her impulses. That, too, will develop with time.