When I was 16 my 1st vehicle was a beat up old 4banger pickup truck. I drove it around for about 6-8months. I don't know about everyone else but I couldn't drive very well to say the least when I turned 16. I didn't pay much for it and sold it for almost what I paid for it. After that I got an 87 LX 5.0 I think I paid a little under 4000 for it (back in 1995). My dad did not like the idea very much, but my mom being the pushover she is hooked it up. After I got the car the only problem I had between my dad and the mustang was them frequently disappearing together.
It was probably was a good idea getting one with an AOD (although I wanted a 5-speed) It kept me somewhat out of trouble although I did come close to biting it a couple times. If I was you I would get a beater to drive around for a little while why you save money, learn to drive, keep out of trouble, and build on your fathers trust. At that point sell the beater and get the V8 mustang. My $.02.