If you are just talking about safety, In your parents eyes it all boils down to air bags vs no air bags. Guess which one wins. I do have to agree on that point. No matter what driving skills you have, It will always be the other guy that's going to do something stupid. In a car that small, think again which one will win. I think about that every time I get into mine. It's 1977 safe, not 2015 safe.
You don't seem to be a "silly kid" so I'm not telling you not to get a Z but you have to realize most everybody that owns one has something else to drive. Do choose something worth driving every day and when it is feasible, get that Z and enjoy every minute of it. And When you do, A coupe would be my personal choice, but I've never driven a 2+2 so my opinion may be considered lopsided (also my daughter is about to turn 16 ).