Start with a car your not afraid to wreck, and can keep running with a reasonable budget. Everything else is second.
I had a 97 Cherokee then and it was a fantastic car to get into the hobby with. It required work but parts were cheap and it was easy to fix. I also got to do a fair amount of offroading with it, and that will teach you car control quick. Not to mention there was really only so much trouble it could get me in.
This is all a polite way of saying you should pass on the cobra. Im glad I didn't get mine until I was out of college and had a decent job because looking back I would have probably made some poor decisions not to mention the financial aspect of it.
Personally I would start out in something else, not saying that you cant handle it but its nice to cut your teeth on something with a little less snap to it, especially if it is your first manual transmission car. I started out when I was 18 in a 99 Mustang GT and modded it along the way until I sold that and purchased the 03 when I was 23 and am glad I went the route that I did.
Do it and never look back. When I was 18 I had Chevy's loved them and will do, but here's the thing. I could have spent that on the car I have now back then. You are going to have something fast or with speed parts buy your cobra and leave it stock for a couple years. My chevys 69 3/4 truck with a big block best pass 14.0 102 mph. SS 68 4 speed elcamino 550 HP by the time I was 20 now sold. Buy what makes you happy but please don't race it on the street keep it to early summer freeway runs. They move to quick your liable to kill your self or the person walking on that cross walk you are going way to fast to see. If you want to show off take your friends to the track and blow there doors off at test and tune.