My first car was a 1987 Subaru gl wagon...ohhh man but did I then upgraded!...to a 1990 subaru legacy...wagon...then I got myself a 300ZX and now the 370Z.
I think the OP is kinda mature, he is even asking if the Z is too much and if he should wait 'till college, and to that I say YES. How about a 240sx for now? RWD so you can get used to it, decent power and good looking. It even has back seats!