"LISTEN KID," You're going to find that guys who are older and largely stupid and unsuccessful are always going to bash you on the internet for having nice things. This is mostly due to their own jealousy and lack of the ability to earn the amount of money needed to buy comparable things, even at twice, sometimes three times your age. I live on Long Island where I've seen many, many of my peers get "high school graduation presents" of brand new BMWs, Lexus, or a $30k WRX as their first car from their parents. I built, bought, and sold Mustangs and various other muscle cars in my late teens and early twenties and always had some jealous 45 year old Wal-Mart cashier online try to tell me my parents funded the project. Meanwhile, I was smart with my money and did everything myself.
I do believe that you built your car yourself with your own money, and you did a damn good job at that. If your grandparents and parents were/are entrepreneurial and successful and made a great life and future for you, then more power to them. That guy who has a bone to pick with you on here is trying to come down on you for your tenacity and success at the hobby because he can't have the things you have, though he wants them. He can't write a punctuated sentence to save his life, and that may or may not be a reflection of his income bracket. Keep doing what you're doing and enjoy what you have, as there'll always be someone on the other side of the fence with piss in his cheerios, moaning about how much greener your grass is.