Try some performance racing schools. Just about every big road course track has a dedicated one. Find out then, if you actually have any natural talent.
Why don't you start small and at least attend some autocross events. Its a good cheap way to get some some basic seat time, and learn a car's limits, because as good as Grand Turismo is, its not a replacement for really being behind a wheel, even if its slow and on a course with just cones.