learning - Why do children call themselves by their name?

Why is that young children call themselves by their first name when referring to themselves? This question is similar to Speaking in the third person; however, young children do not understand the connotations of speaking in the third person.

My fiance's cousin who is six refers to herself as ゆりちゃん. Is the only reason she calls herself by her own name because everyone calls her ゆりちゃん when talking to her? When do children stop referring to themselves in the third person and why?

Answer

@JesseGood's answer is correct, but just to add to it:

Not only will other people refer to kids by their name, they will often also refer to themselves by title when speaking to them. I.e. their mother/father will likely refer to themselves as "お母さん/お父さん" or "ママ/パパ" and their teacher to him/herself as "先生" when speaking to them. They might not hear personal pronouns much at all in their daily lives.

Thus, it's not surprising that kids learn that people have a label which is used independently from who is using it. Kids have to learn to use pronouns at all, which is quite different from the problem of learning to use I/you correctly, which seems to be common in languages where pronouns are more commonly used.