What criterion is necessary to become an american citizen?

If your mother naturalized before your 18th birthday you would automatically become a citizen, no test, no paperwork. But she would have to be sworn in as a citizen for that to happen, 

As it is you have to be a permanent resident for five years to apply to become a naturalized citizen. The date that starts is essentially the date you got your green card and assuming you have not been out of the US for more than six months as any time since