Think about it this way: You are where you are. You are not where you are not. You would say, "I am here," because you cannot say, "I am there." They very definition of, "there," is not the present location, A.K.A., not here.
So, I can say that I am here, and I will always be right. That means that by saying, "We're here!" I am not stating that I am in a specified location, like at the restaurant where I am meeting people, but that I exist at a location.
Similarly, the familiar annoyance of, "Are we there yet?" holds no water. "We," can never be, "there," because, "we," always exists in the place that they exist, which is always, "here."
Now, let's all go on from here speaking with correct usage of the words here and there. Remember, we can only be here, because there is not here; it's a letter away.