Performance driving school sounds like something useful for track day not regular driving on a public road.Knowing how to drive a car with the goal of gaining maximum performance does not really equate to skills that are the best for safe driving in a public setting.
Top Gear having fun in a controlled track setting=Performance driving school
Driving safely on an open public road in an uncontrolled setting=Defensive driving school(better one that teaches students how to safely control their car in hazardous conditions.)
You may also have not had any accidents because you are only 17 years old(Happy belated B-Day by the way I forgot to post in your thread.) and have not been exposed to the many hazards of driving on a public road for very long.
Im not trying to nag you or anything I am just telling you to keep in mind not matter what training you have had you still only have a few years at most driving experience and people your age at the greatest risk of death or injury in a car accident even more so than old farts with false teeth a Buick and no vision thanks to popping Viagra pills.
I have been driving since before you where born and I have only been in one accident in which I was driving a vehicle involved.(I have been in 4 where I was a passenger)It was the other guys fault he was not paying attention and rear ended me. I have avoided many accidents though over the years because my dad taught me to be a very good driver and alert.I have performance experience from time attack driving but I also know that much of that knowledge does not necessarily apply to safely driving down the street.
I would say just brush off the urge to do something to a tailgater and just let him pass you if he crashes into you its not your fault(if you drive safely) if the person is doing it to be annoying then he will get no rise from it if you show no sign of it bugging you and he will probably go home and cry into a pillow while he wears a "Tap Out" shirt.Remember guys that tailgate you in lifted trucks that are spotless and have obviously never been used for true off roading or mudding more often than not are trying to compensate for something else being lacking.

So in the long run you are better off in every respect.