So if everything has a beginning who created Jehovah - whoever created him should be God."
That is the CUTEST thing that I have read from a child in quite some time.
(of course, it makes me think that this comment then means that the wts should be God, as they invented "jehovah" as they deemed fit)
I'm not sure how that is telling you that she is an atheist though. She is just questioning things that don't make sense according to other things that she is learning. However, even if she does go that route... don't worry... it is her path to walk. You owe her love, first and foremost... and she will find her way, or perhaps she will be found. I was not raised in religion, and no one taught me my faith. But here I am just the same.
Also, kids go through the phase that teachers know everything, and parents never know more than teachers, so the things learned in school are... for lack of a better word... gospel ; ) Your daughter sounds about the right age for that... but be prepared becasue teenagers are worse, lol.
As to her question, I wouldn't worry about it. (and I imagine it might be bothering you, not that she is asking, but because you don't have the answer yourself... kids have a good way of keeping us honest.) It is true that science states that everything has a beginning (I think science states that)... but also that science can only speak to that which it CAN measure. But there are some things that are outside the "current" knowledge of science, and beyond the scope of the current tools that we have. When new evidence is discovered... or better tools to create more updated theories... then the statements of science are updated.
Science does not know how to measure God... so it cannot make statements as to Him.
Peace to you and your little one (and the rest of your loved ones),