I got a $10K loan at age 18. Was the only way for me to get a car. I worked casual but paid it off. I guess it depends how responsible your SDD is.

Yeh the only thing about wanting a flash car is she may not get anyone to insure it at her age and driving experience or it might cost heaps and i think if she has a car loan its part of the contract that she has to have comprehensive insurance.
I remember my brother bought a V8 SS commondore and had problems getting insurance as he was under 25 at the time.