I do know the who, where, and why of my life, at least to some degree anyway.

My parents and their love helped to create me, their parenting and genes affected me greatly.

Yes it matters to know ourselves well, that's how we change and grow as people. How we are in the world helps others or can hurt others.

To be surprised by something we had in ourselves shows that we're aware of ourself, which doesn't happen in the animal kingdom with other animals. What we do with what we learn about ourselves is what counts, no?

I'm dang thankful that it feels as if I'm constantly learning and emerging as a growing person, that's a process I hope continues until I breathe my last breath!

Until I became a Christian, I didn't know the answer to those questions. As I grew in my faith I realized I did now understand why I am here and who I was. So my take on your questions would be from my Christian POV and it would be this:

Who am I?

I am a child of God.

Where Am I?

I am safe in his hands as I go about doing my best to seek his will for my life.

Why Am I?

I take this to mean, why am I here? If so, I'd say, I am here to glorify God.

The Westminster Confession of Faith of 1646 coming out of the great leaders of the Reformation of the 15th and 16 centuries said that "the chief end of man is to glorify God."