"I am." is in constant motion.

We can only know 

what, not who, we were

because we are constantly evolving,

constantly changing.  

I am not who I was when I was ten.  

I am not who I was when I was fifty. 

 I will not be tomorrow who I am today.  

The sentence: "I am." is in constant motion.

How your "I am"  turns out is up to you.