Actually, she's right. Islam has been there since the beginning of time. But time traveling Jews went back and erased all evidence of its existence, and substituted a distorted version of it several thousand years ago. God waited until he thought we were ready to learn of the true original religion again, when it was passed down to a prophet to give us the knowledge back.
I would have just smote them and erased all history of them, but the big guy works in mysterious way.
And before anyone asks, no you can't have what I'm smoking, I need all of it!