First, you want to be careful about with who are you talking on Facebook, you need to know that those persons are real and that their intentions are good, personally I would talk with them first about meeting one day and create a trust relationship.
Make sure to practice your english because not everyone speaks spanish in the USA and it could be harder to you understand what they are saying or talking about, try to investigate and know more about their culture and consider all your options. That's my advice.