Eighteen is the age of majority for such decisions, but one needs to fully understand that decision. If it's to go live with the other parent, than it still needs court approval, but going to live with friends, or alone needs to be clearly thought out. It's not the age that makes you an adult.
see link
I believe the age is 13
No, that is up to the parents to decide.
you can move out of your parents house=]
Eighteen.
Totally legal unless your custody agreement says otherwise.
They need to file for custody
No, you file to have the custody and support order set aside.
Yes until a modification is approved.
Yes. if the custodial parent can not take care of the minor the non-custodial have first dibs.
At 18, you are considered a legal adult and emancipated from your parents. you are free to do as you like. no your an adult they can't say a word your eighteen
yes
No, visitation and child support are 2 separate entities. The only way this would affect your support amount is if you are set up with 50-50 custody and the child stops going to the other parents house and you take them to court to get primary custody.