I want to know something about the marriage .

In america, you do have to be a certain age to be able to marry.

There are exceptions to this rule of course, but they involve the parents.
If a child under the age of 18 wants to get married, they have to have their parents sign wavers, and appear in a court room in front of a judge saying they think it is ok for their kid to marry and then give a reason why.

If the judge thinks it is ok, they will sign that same waiver, and the child can get married.
If not, then the child has to wait until 18 years old.

Here is a summary of legal marriage ages in each of the 50 states in the United States.

http://www.coolnurse.com/marriage_laws.htm

The interesting thing is, that in the US, the age that people are getting married is rising.

http://www.infoplease.com/ipa/A0005061.html

In the 1950's-70s both men and women married rather early. This is no longer the case. Women are also having their first child later in life than in earlier times.