Is a 1997 audi a4 1.8t with 104,000 miles for $5690 dollars a good deal? its for a 16 year old?

It will be very expensive to repair and with that many miles on it the car will probably need maintenance quite frequently. For a 16 yr, I'd go with a used accord or civic, will be pretty cheap, safe, and inexpensive to insure, and not need nearly the maintenance.