I will just come out and say it, the fact that you want a classic car not only straight off the bat but for use as a daily driver or something really shows how little you know about driving in the real world.
I know 60's mustangs are cool but fact is since it's a 40 year old car it has ZERO as far as modern safety features go, lousy gas mileage (even the I6), iffy handling, and just really fails across the board if held up to all other modern standards, As well as the obvious fact that you have no idea what you're doing behind the wheel of any car (past the minimum the state allows) it is probably the worst car you could get.
Mustangs in general (new or old) cost a fortune for kids/greenhorn drivers, but w/ a classic you're just asking to pay even more and possibly hurt yourself even more than you probably will w/ a modern one w/ airbags and crumple zones (given the stats on teens w/ mustangs)
Seriously, just get a cheap/reliable beater for now while you learn not to hit stuff when you drive. And save the classics for when insurance doesn't cost your parents a second mortgage and you actually have a better chance of keeping it in one piece