Most everyone on this forum will recommend like wok said TrackDaze and NASA. Both groups have excellent on track and classroom instruction that keep it super fun and safe. No one went out on track the first time and got an F1 ride. Everyones learning curve is different and both of these two organizations understand that and can take you from super green novice to seasoned HPDE champion to W2W racer. Just make sure your car is safe, you have the proper helmet and better from brake pads help too.

Like I said you cant go wrong with either of these 2 groups.