Nice cars those WRX's. I've raced against a few and they are very capable. I'm going to assume that my son will one day be into sports cars, both my wife and I race MX and various SCCA events including Trials and Solo. When he is ready to drive he will attend one or more of these:
http://www.scca.com/about/?cid=44408
There is no way I'd put a teenager into a car as capable as the WRX without formal aggressive/defensive driving skills. If you weren't aware of this type of training please follow the link and get her signed up.