Even as your second car you're going to put the car in a lamp post.
I'm not being an asshole it's just proven fact. You could be the best damn driver in the world but at 17, all it's going to take is a Friday night and a couple of other 17 year olds in the backseat to make you do things
we've all done at that age.
Except most of us were driving cars with two digits of torque
(and yet, the shit I used to get myself into..)
You say you like cars and you like working on cars? Pick up something older that's depreciated enough that you can sell it for what you got it for a year later, and cheap enough that if (
when) you slide into a ditch you can walk away from it. If you actually manage to walk away from this without crashing the car then sell it after a year or two and you'll have enough for the M3, except now we won't see you on the news.
Also, whatever you get (and I bet you'll get the M3 because you're 17 and there's no fuckin way a 17 year old is going to say no to an M3), bring it out to autocross. Learn some car control. You're going to see exactly what it takes (surprisingly little) to lose control of the car, and then you're going to figure out how to recover if (
when) shit happens.
This was probably a waste of my time, I just figured I'd try.