Double 'I'

I stare at the mirror,
It stares back at me,
I smile,
It smiles back,
I laugh,
I can hear silent echo from moving lips,
I raise my right hand,
It raises it's left,
It does look like me but I am not sure,
I see it everyday,
it does look familiar and yet so different,
do I see myself or do I see what I want to see?
I have seen myself grow,
a happy child to a grumpy teenager,
first tooth falls to curvy lips,
childlike to a woman inside,
my body a cover,
ready to be crumpled and wrinkled,
what am I?
What are you?