Conclusion
Andrea has a number of problems and none of them is going to be solved easily. The fact that she is sexually turned on to blacks is not a great disaster these days. The fact that she is a fourteen year old girl who is anxious to have a relationship with a specific adult black man, is a problem.
She keeps emphasizing the fact that she had never even had any black friends, and yet her fantasies take her back to Africa where she would be the outsider in a black world.
Andrea is obviously rebelling against the life she has known and the world she has known. She needs to meet different types of people and associate with different worlds. She has been stifled too long among the rich upper crust in the 'right schools'.
Once this girl has a chance to meet people of a variety of backgrounds and types, she will be better prepared to choose a sex partner.