Trainer or not!?
What a lot of people tend to forget is that being able to fly an airplane around the field does not mean that you are a good pilot. You may be able to control the plane in a nice rectangular pattern, or do "figure eights" around the field, but what do you do when you make the inevitable mistake? Do you get yourself out of trouble, or do you "dumb-thumb" it into the ground? 99 out of 100 rookies will will just compound the mistake by panicking, and making the wrong corrective move, and wind up bringing their airplane home in little bitty pieces.
A good analogy here is to think of a teenager (YOUR TEENAGER) who just got his drivers license. Now, he wants to drive YOUR FERRARI! He thinks he knows how to drive. After all, the State just gave him a license saying so. But YOU know better! You know that he can control a car, at a moderate speed, but can he AVOID an accident should the situation arise? Probably not. Is he aware that such a powerful engine in such a well engineered chassis will respond much differently than the old Toyota that he learned on? So you tell your teenager: "No, you can't drive the Ferrari."...
And then you go out and buy a model airplane that you are not ready for.
I have a soft spot for warbirds too. Why not "Pay your Dues" with a Cub dressed in the L-4 colors?