As atheism raises especially among young people, are you scared that we may have an atheist president one day?

It is actually better to have an atheist, and basically they have been largely atheist through the 20th century, because the religious G. W. Bush held back scientific research on stem cells for 8 years, and Clinton wasn't much better than Bush in that regard when he placed restrictions on it. Having a religious president is like having a theocracy. It impedes scientific progress and threatens to make the USA a second rate country technologically.