Travelling

Hi, if you can answer the following questions( or any one of them) it would be greatly appreciated home land is Trinidad

Questions:-

1) How long can you visit california with a normal passport?
2) I know that the max is 6 months, but if you stay for a full 6 months, do you have to go back to your home land for 6 months before you can stay for 6 months again?
3) Does the elderly get extra time to stay in california