Hi, Fern! Welcome to the Comparative Religion board!
Your questions are only among the deepest and most important of any we can ask ourselves. As such, I'd shy away from easy or superficial answers and from religious dogma.
One problem within this western culture of ours appears to be a tendency for us to confuse who we are with what we do. I'm a father, a husband, and a writer, but none of these separately or together tells me who I am.
"Why am I here?" is equally problematical. If we buy into the notion that what we do = who we are, then the answer is superficial and unsatisfying, i.e., I'm here to write more books and you, at least until now, were here to raise your kids.
And, unfortunately, for the majority of folks in the West, equating doing with being is just fine. Go to work to pay the rent and buy the groceries to shelter and feed the kids . . . it works for millions of people.
A few of us go deeper than this, however, and this is where our personal and individual concept of the Divine comes to the fore. Having a purpose in life implies that we either were put here for a reason, or that we chose to be born for a reason. Learning what that reason might be is the point, it seems to me, of our life's path, and goes a long way to answering the second of the two questions.
Who are you? I would say that you are an expression of the Divine on this world, here to learn, to grow, and to manifest the Divine in your life; you might say roughly the same thing by saying that your are a child of God.
Where you go from there, of course, is up to you!