[Airina]

Nope X is the worst, then its NC - 17, then R, then PG - 13, then PG, then G.
X if i remember correct you have to be over the age of 18 or 21, NC - 17 you have to be at least 17 no matter what even with parents, R you have to be either 17 or have a parent present, then PG - 13 is just advised to not be shown to kids under the age of 13, PG is just parental guidance, then G is for general audiences.