Crystel,
You're an adult. You know what's right and what's wrong. You need to make up your own mind as to whether you sell to your neighbour, and at what price. As you are already aware, $12,000 is a good price for an FC, and it certainly makes a good profit for you.
...but you have to live with yourself, and you have to live with your neighbour. Remember, you'll be seeing this person frequently, if not every day. You'll also see your neighbour driving your car. How will you feel? If the answer is "Comfortable", then do it.
I see you've found Fast Eddie's car on this site - compare your car with his to get some idea of what yours is worth - remember he was originally asking $10,000 for his but he wants to sell it quickly. In my opinion, Edward's is worth the $10,000 he's asking - I'd buy it if I was allowed!!!
Consider your position.
Good luck.
Martin