Your dad buying you one, then transferring it to you would be called a straw purchase. You can own a handgun at 18, but you can't get it from a dealer until you're 21. 18-20= private transaction only. You still need the purchase permit, but no form 4473.
The loophole is that your dad can get you one as a gift, and mark it as such on the form 4473. I'd suggest a handgun for your 18th birthday.