15 grand can buy you an E36 M3 in great condition. People around here will disagree with me, but a modded E36 M3 is too much for a 16 yr old with no solo driving experience whatsoever, let alone one who didn't learn to drive in a rwd car. A stock one, fine, but we all know you won't leave your car stock so dont front that you would.
A used accord coupe (2001ish) is a nice SAFE car that would be good for a first driver, you could get one for about 15 grand and its one of the safest cars on the road.