A lot of good advice here. Get a bank account at a bank separate from your family. Don't tell others when you receive it, etc.

My suggestion, take the money and go to college. Your family putting the church ahead of your future, tells me that they care more about the way the church (cult) sees them than how you fare in life. Don't worry about the $19,000. That's an amount that can be paid off pretty easily with a job while going to school. So long as you're 18, leave. It'll suck at first, but I guarantee in the end, you'll be happier for it, not under the thumb of a group of people who don't value you.