Sisters ROCK!

So, on our ride to school this morning (me, Livi and Livi's friend) the girls start talking about the tooth fairy.  Normal things a 3 & 4 year old would say.  You know, how they can't wait, and how they are going to put their tooth under the pillow etc.  So Livi asks how much longer till she will get a visit from the tooth fairy.  I tell her probably when she's about 5 or 6.  She immediately responds "Juju is 5!".  So yes, we talk about how Juju will probably loose a tooth sometime soon etc.  When all of a sudden her friend asks, "Why is Juju 5 and she can't talk?"  It was said with no ill intent and completely innocently from a 4 year old, but I have to say it caught me completely off guard.  Like a jab to the gut.  I sat their speechless, like how do I explain this to a 4 year old.  Do I start off by saying she has Rett Syndrome which causes apraxia.  And how her brain is not communicating with body and she is basically trapped in a body that doesn't work.  But that she totally understands everything etc.  So as I sat there for a nano second contemplating how to handle this, Livi, with out skipping a beat very defensively announces, "Yes she can talk!  You just have to look at her eyes and she will talk to you.  You can also ask her yes and not with her buttons and she has a talking computer."  And her friend, satisfied with her answer, said, "Oh."  Why can't I think as fast as my 3 year old daughter?  Why?  Because my heart is not as pure as hers.  She is completely oblivious that anyone might think her sister is "different".  She just loves her big sister with all her heart and is more than ready to defend her.  Thank God for sisters.