It differs from state to state.
You can marry ANYONE you want. Well, as long as the person is of the opposite sex (depending on the state) and of legal age.
Whats Kava?
You can marry at any age as long as you have consent from your parent or guardian.
If you are legally capable ( single and with the legal capacity and of legal age , you can marry anyone that you choose as long as the other party is single as well, then you can petition him as a spouse and he can later become a green card holder ( a US Resident ) US citizens are permitted to marry foreigners as long as the marriage is valid and real, and not for purposes of evading Immigration Laws.
In the US, as far as I'm aware, you can marry in every state at 17 IF you have parental permission.
Yes. Unless you marry with a person of the same sex, which is possible in Belgium, but not in the US.
marry him
Yes you CAN marry, but that will NOT give him LEGAL status.
If you're in the US, the age is 18.
NO!
yes you can
It is not legal to marry your own daughter or granddaughter anywhere in the US.