series1- That Supra is a cool car, sounds like it was set up sensibly. I don't think the automatic is a bad thing at this point; you can concentrate on everything *except* shifting.
Heh heh...[Insert lecture about being more responsible than *I* was at your age here

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Check out a used-book website and pick up Bob Bondurant's books on High Performance Driving and Police & Pursuit Driving. He covers a *lot* of stuff you'll find useful and the info will be good to have in mind before you do a driving school.
And yeah, you can still go to track events with automatics; my wife and I have done it and we weren't handicapped by the transmissions.
And heh heh#2...that black paint will be a real test of your wash technique; I strongly encourage you to get a foamgun
That's a mighty clean Trans Am too!